JP2008008806A - Method and apparatus for evaluating surface flaw length by eddy current flaw detection method - Google Patents

Method and apparatus for evaluating surface flaw length by eddy current flaw detection method Download PDF

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JP2008008806A
JP2008008806A JP2006180640A JP2006180640A JP2008008806A JP 2008008806 A JP2008008806 A JP 2008008806A JP 2006180640 A JP2006180640 A JP 2006180640A JP 2006180640 A JP2006180640 A JP 2006180640A JP 2008008806 A JP2008008806 A JP 2008008806A
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output voltage
eddy current
distribution
coil
defect
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JP4311416B2 (en
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Akira Nishimizu
亮 西水
Yoshio Nonaka
善夫 野中
Isao Yoshida
功 吉田
Motoyuki Nakamura
基征 中村
Akihiro Taki
明寛 瀧
Masahiro Koike
正浩 小池
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Hitachi Ltd
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Hitachi Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
    • G01N27/9046—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents by analysing electrical signals

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating a length of the surface flaw of a metallic inspection target by an eddy current flaw detection method without relying on visual examination or permeation flaw detection using a scale. <P>SOLUTION: An exciting coil 1 and a detection coil 2 are scanned on an open test specimen 3 in the direction shown by an arrow, and the output voltage at each scanning position is measured on the basis of the output of the detection coil 2 by an eddy current flaw detection device. From the data of a distribution curve 5 of output voltage showing the distribution of output voltage at each scanning position, within a differential voltage range Vp-p descending to a left-hand side from the maximum left-hand value, 12 decibel down position data is extracted, and within the differential voltage range Vp-p descending to a right-hand side from the maximum left-hand value, the 12 decibel down position data is extracted and the distance between both position data is calculated to be evaluated as the length of the slit 4 being the surface flaw of a test specimen 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、金属製の被検体に存在する表面欠陥の存在範囲または長さを渦電流探傷法で得られる出力電圧分布を用いて求める技術に属する。   The present invention belongs to a technique for obtaining an existence range or length of a surface defect existing in a metal object using an output voltage distribution obtained by an eddy current flaw detection method.

渦電流探傷法とは、励磁コイルに交流電流を流し、その励磁コイルを金属製の被検体の表面に近づけると被検体には渦電流が誘起され、その渦電流が被検体に存在する欠陥（例えば、被検体の表面に開口している亀裂）などの構造不連続部の影響を受けて変化し、その変化に応じてその渦電流に依存する磁界も変化し、その磁界の変化で、その磁界内の検出コイルに生じている誘起電力も変化し、その変化から、被検体における欠陥の有無を検出する方法である。   In the eddy current flaw detection method, an alternating current is passed through an exciting coil, and when the exciting coil is brought close to the surface of a metal subject, an eddy current is induced in the subject, and the eddy current exists in the subject. For example, it changes under the influence of structural discontinuities such as cracks open on the surface of the subject, and the magnetic field that depends on the eddy current also changes in accordance with the change. In this method, the induced power generated in the detection coil in the magnetic field also changes, and the presence or absence of a defect in the subject is detected based on the change.

その渦電流探傷法を表面欠陥の検出に用いた例が非特許文献１に掲載され、同じく薄肉管の表面および内在欠陥の検出に用いた例が非特許文献２に掲載されている。   An example in which the eddy current flaw detection method is used for detection of surface defects is published in Non-Patent Document 1, and an example in which the surface of a thin-walled tube and detection of intrinsic defects is similarly published in Non-Patent Document 2.

また、渦電流探傷法で発見した欠陥の長さを評価する規格がないため、校正されたスケールと目視検査または浸透探傷検査との組み合わせで長さを評価していた。   In addition, since there is no standard for evaluating the length of defects found by the eddy current flaw detection method, the length was evaluated by a combination of a calibrated scale and visual inspection or penetration flaw inspection.

西水、小池、松井、フレキシブルマルチＥＣＴセンサの開発、第８回表面探傷シンポジウム講演論文集（２００５）、ｐｐ１３９−１４２Nishimizu, Koike, Matsui, Development of flexible multi-ECT sensor, Proceedings of 8th Surface Inspection Symposium (2005), pp139-142 川田、川瀬、黒川、インテリジェントＥＣＴシステム（蒸気発生器伝熱管検査用新型ＥＣＴ（渦流探傷）システム）、検査技術６月号（２００５）、 ６６−７２．Kawada, Kawase, Kurokawa, Intelligent ECT system (new ECT (eddy current flaw detection) system for steam generator tube inspection), Inspection Technology June issue (2005), 66-72.

金属製の被検体に生じた表面欠陥の長さや表面欠陥の存在範囲を、校正されたスケールと目視検査または浸透探傷検査との組み合わせで行う場合、水中に有る狭隘部が検査部位である場合や水が張られている大型容器の底部では、浸透探傷検査が困難であり、且つカメラを用いた目視検査も必要な照明の不足や検査部位の表面に堆積した付着物や酸化膜により欠陥の一部が確認できない可能性があった。   When the length of surface defects generated on a metal specimen and the range of surface defects are to be combined with a calibrated scale and visual inspection or penetrant inspection, the narrow area in water is the inspection site. At the bottom of a large container filled with water, penetrant inspection is difficult, and visual inspection using a camera is necessary. There was a possibility that the part could not be confirmed.

この様な背景により、目視検査や浸透探傷検査に依らない欠陥の長さ評価方法が必要となった。   With this background, a method for evaluating the length of defects that does not rely on visual inspection or penetrant inspection is required.

本発明の目的は、渦電流探傷法を利用した被検体の表面欠陥の長さの評価方法とその装置を提供することにある。   An object of the present invention is to provide a method and apparatus for evaluating the length of a surface defect of an object using an eddy current flaw detection method.

この目的を達成するために、第１手段は、渦電流探傷法による表面欠陥の検査において、表面欠陥による出力電圧の分布を用いて、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法である。   In order to achieve this object, the first means evaluates the existence range of the surface defect or the opening length of the defect by using the output voltage distribution due to the surface defect in the inspection of the surface defect by the eddy current flaw detection method. A surface defect length evaluation method characterized by the following.

第２手段は、表面スリットを探傷した時の出力電圧が実質的にリサージュ波形のＹ軸方向に出力する条件に設定し、表面欠陥を探傷した時に得られるＹ成分の出力電圧が、連続的な上に凸の分布をもつ場合は出力電圧の最大値を利用し、また、出力分布が不連続的な分布をもつ場合は出力分布の周辺付近に現れる偏曲点を利用して、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法である。   The second means is set so that the output voltage when the surface slit is detected is substantially output in the Y-axis direction of the Lissajous waveform, and the output voltage of the Y component obtained when the surface defect is detected is continuous. If the output has a convex distribution, use the maximum value of the output voltage.If the output distribution has a discontinuous distribution, use the inflection points that appear near the periphery of the output distribution. It is a surface defect length evaluation method characterized by evaluating the existence range or the opening length of a defect.

第３手段は、第２手段において、Ｙ成分の出力電圧が連続的な上に凸の分布をもつ場合、無欠陥領域の出力電圧を基準とし、その基準と出力電圧の最大値と１／２以下の任意の閾値で切った出力電圧分布の断面あるいは線から、また、出力分布が不連続的な分布をもつ場合、無欠陥領域の出力電圧を基準とし、その基準と出力分布の周辺付近に現れるプラスの偏曲点の出力電圧の１／２以下の任意の閾値で切った出力電圧分布の断面あるいは線から、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法である。   In the second means, when the output voltage of the Y component has a continuous upward convex distribution in the second means, the output voltage in the defect-free region is used as a reference, and the reference value and the maximum value of the output voltage are halved. From the section or line of the output voltage distribution cut at any of the following thresholds, and when the output distribution has a discontinuous distribution, the output voltage in the defect-free area is used as a reference, and the reference and the vicinity of the output distribution The surface characterized by evaluating the existence range of surface defects or the opening length of the defects from the cross section or line of the output voltage distribution cut at an arbitrary threshold value of 1/2 or less of the output voltage of the positive deflection point that appears. This is a defect length evaluation method.

第４手段は、第３手段において、出力分布の周辺付近にプラスとマイナスの偏曲点の対が現れる場合は、マイナスの偏曲点の出力電圧を基準とし、その基準とプラスの偏曲点の出力電圧の１／２以下の任意の閾値で切った出力電圧分布の断面あるいは線から、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法である。   In the fourth means, when a pair of plus and minus inflection points appears in the vicinity of the output distribution in the third means, the output voltage at the minus inflection point is used as a reference, and the reference and the plus inflection point. A surface defect length evaluation method characterized by evaluating a surface defect existence range or a defect opening length from a cross section or a line of an output voltage distribution cut at an arbitrary threshold value equal to or less than 1/2 of the output voltage of is there.

第５手段は、渦電流探傷法による表面欠陥の検査装置において、連続的な上に凸の分布をもつ場合は出力電圧の最大値、また、出力分布が不連続的な分布をもつ場合は出力分布の周辺付近に現れる偏曲点を利用して電圧最大変位を求める手段と、出力分布と入力部からの閾値とを比較し、閾値を越える断面距離または２地点の距離を算出する手段と、該距離を表示する表示部を有することを特徴とする渦電流探傷装置である。   The fifth means is an inspection apparatus for surface defects by an eddy current flaw detection method, in which the maximum value of the output voltage is obtained when the convex distribution is continuous and the output is output when the output distribution is discontinuous. A means for obtaining a maximum voltage displacement using an inflection point appearing in the vicinity of the distribution, a means for comparing the output distribution with a threshold value from the input unit, and calculating a cross-sectional distance exceeding the threshold value or a distance between two points; An eddy current flaw detector having a display unit for displaying the distance.

第６手段は、被検体の表面欠陥を検査する渦電流探傷法において、該表面欠陥による出力電圧の分布に基づき、該表面欠陥の存在範囲または欠陥の開口長さを検査することを特徴とする渦電流探傷法である。   The sixth means is characterized in that, in the eddy current flaw detection method for inspecting the surface defect of the subject, the existence range of the surface defect or the opening length of the defect is inspected based on the distribution of the output voltage due to the surface defect. Eddy current flaw detection method.

第７手段は、被検体の表面欠陥を検査する渦電流探傷装置において、該表面欠陥による出力電圧の分布に基づき該表面欠陥の存在範囲または欠陥の開口長さを算出する手段を備えたことを特徴とする渦電流探傷装置である。   The seventh means is an eddy current flaw detector for inspecting a surface defect of a subject, comprising means for calculating the existence range of the surface defect or the opening length of the defect based on the output voltage distribution due to the surface defect. This is an eddy current flaw detector.

本発明によれば、目視検査や浸透探傷検査に依らないで、被検体の表面欠陥の開口長さを評価できる。   According to the present invention, it is possible to evaluate the opening length of the surface defect of the subject without depending on visual inspection or penetration inspection.

最初に渦電流探傷法を以下に説明する。図２のように、金属製の被検査体である試験体３（被検査体３とも言う）に、試験体３の表面に開口するようにして、亀裂などの欠陥を模擬して、スリット４を加工して設けてある。このスリット４の深さは、図２の場合はスリット４の長さ全長にわたって一定である。そのスリット４を渦電流探傷法で検出する方法を実施するために、渦電流探傷装置が用いられる。渦電流探傷装置の渦電流探傷器に接続されている渦電流探傷用プローブ（以下、単に渦電流プローブという。）は、図２に示すように、励磁コイル１と、それに隣接した検出コイル２とで構成されている。励磁コイル１と検出コイル２とは、探傷プローブが移動すると、その移動の方向へ励磁コイル１と検出コイル２とが同時に移動することが出来るようにユニット化されている。   First, the eddy current flaw detection method will be described below. As shown in FIG. 2, the test object 3 (also referred to as the test object 3), which is a metal test object, is made to open on the surface of the test object 3 to simulate a defect such as a crack, and the slit 4 Is processed. The depth of the slit 4 is constant over the entire length of the slit 4 in the case of FIG. In order to carry out a method for detecting the slit 4 by an eddy current flaw detection method, an eddy current flaw detection device is used. As shown in FIG. 2, an eddy current flaw detection probe (hereinafter simply referred to as an eddy current probe) connected to an eddy current flaw detector of an eddy current flaw detector includes an excitation coil 1 and a detection coil 2 adjacent thereto. It consists of The excitation coil 1 and the detection coil 2 are unitized so that when the flaw detection probe moves, the excitation coil 1 and the detection coil 2 can move simultaneously in the movement direction.

渦電流プローブをスリット４が開口している側の試験体３の表面上に配置すると、交流電源が接続された励磁コイル１から発生する磁場により試験体３内に渦電流が流れる。また、この渦電流が形成する磁場は、検出コイル２と差交する。その結果、検出コイル２に誘起電圧を生じ、検出コイル２が誘起電圧を渦電流探傷器に送信する。   When the eddy current probe is arranged on the surface of the test body 3 on the side where the slit 4 is opened, an eddy current flows in the test body 3 due to the magnetic field generated from the exciting coil 1 connected to the AC power supply. Further, the magnetic field formed by this eddy current crosses the detection coil 2. As a result, an induced voltage is generated in the detection coil 2, and the detection coil 2 transmits the induced voltage to the eddy current flaw detector.

この渦電流探傷器内では、検出コイル２からの誘起電圧の値を、試験体３の欠陥の無い部位における検出コイル２からの誘起電圧の値との差分を出力電圧の値として測定し、その出力電圧の値の情報を入力データとして、出力電圧の分布を表示する表示装置へ供給している。また、その検出コイル２の位置座標も出力電圧の分布を表示する表示装置へ供給している。この場合、検出コイル２の位置座標は、探傷プローブの位置座標と言い換えることが出来る。   In this eddy current flaw detector, the difference between the value of the induced voltage from the detection coil 2 and the value of the induced voltage from the detection coil 2 in the part having no defect of the test body 3 is measured as the value of the output voltage. Information on the value of the output voltage is supplied as input data to a display device that displays the distribution of the output voltage. The position coordinates of the detection coil 2 are also supplied to a display device that displays the output voltage distribution. In this case, the position coordinates of the detection coil 2 can be rephrased as the position coordinates of the flaw detection probe.

図２に示すように、この探傷プローブを試験体３の上に配置し、スリット４の上部を図２の白抜き矢印の方向（スリット４の長さ方向）へ移動させると、スリット４により試験体３内の渦電流の分布が変化する。これにより当然、その渦電流が形成する磁場も変化することになる。この磁場の変化は検出コイル２に生じる誘起電圧の変化として現れ、それが渦電流探傷器の出力電圧の変化として出現する。   As shown in FIG. 2, when this flaw detection probe is placed on the test body 3 and the upper portion of the slit 4 is moved in the direction of the white arrow in FIG. 2 (the length direction of the slit 4), the test is performed by the slit 4. The distribution of eddy current in the body 3 changes. This naturally changes the magnetic field formed by the eddy current. This change in the magnetic field appears as a change in the induced voltage generated in the detection coil 2, which appears as a change in the output voltage of the eddy current flaw detector.

本発明の実施例で採用する渦電流探傷法は、上述したように検出コイル２に発生した誘起電圧を探傷プローブの移動の位置ごとに渦電流探傷器に入力して、無欠陥部の検出コイル２の誘起電力を基準にした変化を測定していることになる。その変化は探傷プローブの移動の位置ごとに出力電圧の変化として表示装置に入力され、その表示装置に出力電圧の分布曲線５のグラフとして表示される。このようにして、渦電流探傷装置は、検出コイル２の誘起電圧の変化を、無欠陥部の検出コイル２の誘起電力を基準にして、各探傷プローブの移動位置ごとに表現した出力電圧の分布曲線５を表示装置に表示できる。   In the eddy current flaw detection method employed in the embodiment of the present invention, as described above, the induced voltage generated in the detection coil 2 is input to the eddy current flaw detector for each position of movement of the flaw detection probe to detect the defect-free portion detection coil. The change based on the induced power of 2 is measured. The change is input to the display device as a change in output voltage for each position of the flaw detection probe movement, and is displayed on the display device as a graph of the distribution curve 5 of the output voltage. In this way, the eddy current flaw detector is a distribution of the output voltage in which the change in the induced voltage of the detection coil 2 is expressed for each moving position of each flaw detection probe with reference to the induced power of the detection coil 2 in the defect-free portion. The curve 5 can be displayed on the display device.

渦電流探傷器は、検出コイル２の誘起電圧変化をリサージュ波形として表示できる機能も備えている。このリサージュ波形とは、励磁コイル１に印加する電圧を基準に検出コイル２の誘起電圧変化をＸ成分とＹ成分に分離して表示したものである。渦電流探傷法では、通常渦電流探傷器に備わっているその機能を利用して、欠陥の影響を受けた検出信号のリサージュ波形の位相を回転し、Ｘ軸またはＹ軸のいずれかの軸と一致させ欠陥検出感度を向上させる場合が多い。図２の出力電圧の分布曲線５の各位置ごとの出力電圧は、スリット４を渦電流探傷法で探傷して得られるリサージュ波形をＹ軸に回転させ、Ｙ成分の出力電圧として表示装置に表示することで、図２の出力電圧の分布曲線５を得られる。   The eddy current flaw detector also has a function that can display the induced voltage change of the detection coil 2 as a Lissajous waveform. This Lissajous waveform is a display in which the induced voltage change of the detection coil 2 is separated into an X component and a Y component with reference to the voltage applied to the excitation coil 1. In the eddy current flaw detection method, the phase of the Lissajous waveform of the detection signal affected by the defect is rotated by utilizing the function normally provided in the eddy current flaw detector, and either the X axis or the Y axis is In many cases, the defect detection sensitivity is improved by matching. The output voltage at each position of the output voltage distribution curve 5 in FIG. 2 is displayed on the display device as a Y component output voltage by rotating a Lissajous waveform obtained by flaw detection of the slit 4 by the eddy current flaw detection method. As a result, the output voltage distribution curve 5 of FIG. 2 is obtained.

図２の下部の図に示したグラフは、その表示内容である出力電圧の分布曲線５のグラフを表していて、渦電流プローブでスリット４を探傷した結果の一例を示している。その出力電圧は、スリット４の長さに対応した領域に分布するように発生する。   The graph shown in the lower part of FIG. 2 represents a graph of the output voltage distribution curve 5 which is the display content, and shows an example of the result of flaw detection of the slit 4 with an eddy current probe. The output voltage is generated so as to be distributed in a region corresponding to the length of the slit 4.

しかし、その分布領域から求める長さ（出力電圧の消失長さ）は、実際のスリット４の長さより大きめになる傾向がある。これは渦電流が励磁コイル１の直下のみでなく分布をもつことによる。例えば、励磁コイル１により試験体３に発生する渦電流の分布は次のようになる。   However, the length obtained from the distribution area (disappearance length of the output voltage) tends to be larger than the actual length of the slit 4. This is because the eddy current has a distribution as well as directly under the exciting coil 1. For example, the distribution of eddy current generated in the test body 3 by the exciting coil 1 is as follows.

即ち、図３の（ａ）図のように、試験体３の表面上に励磁コイル１を配置し場合、試験体３に発生する電流方向７の渦電流９は、図３（ｂ）図のように、励磁コイル１の近傍に分布する。図４に渦電流９の分布の様子を示す。渦電流９は励磁コイル１の近傍で大きいものの、励磁コイル１から離れた領域にも達することが分かる。この分布により、出力電圧の分布曲線５は探傷プローブがスリット４にある程度接近した地点から変化が発生し始めることになり、その消失長さはスリット４の長さより長めになる。そこで、次に示す評価方法により、スリット４の長さの評価精度を向上させることにする。   That is, as shown in FIG. 3A, when the exciting coil 1 is arranged on the surface of the test body 3, the eddy current 9 in the current direction 7 generated in the test body 3 is as shown in FIG. Thus, it is distributed in the vicinity of the exciting coil 1. FIG. 4 shows how the eddy current 9 is distributed. Although the eddy current 9 is large in the vicinity of the exciting coil 1, it can be seen that the eddy current 9 reaches a region away from the exciting coil 1. Due to this distribution, the distribution curve 5 of the output voltage starts to change from the point where the flaw detection probe approaches the slit 4 to some extent, and its disappearance length becomes longer than the length of the slit 4. Therefore, the evaluation accuracy of the length of the slit 4 is improved by the following evaluation method.

図５に示すように出力電圧の分布曲線５は、スリット４の両端近傍でピークを持つ特徴がある。また、図５の下図中のグラフの右側に注目するとマイナス側で最小値１１、プラス側で最大値１０を持つ。このマイナス側の最小値１１はスリット４の端部に達する前に発生し、プラス側の最大値１０はスリット４の端部を過ぎた位置（スリット上）に発生する。つまり、スリット４の端部は最大値１０と最小値１１で示される２つの偏曲点の間に存在することになる。   As shown in FIG. 5, the distribution curve 5 of the output voltage is characterized by having a peak near both ends of the slit 4. Further, when attention is paid to the right side of the graph in the lower diagram of FIG. 5, the minimum value is 11 on the minus side and the maximum value is 10 on the plus side. The minus side minimum value 11 occurs before reaching the end of the slit 4, and the plus side maximum value 10 occurs at a position (on the slit) past the end of the slit 4. That is, the end portion of the slit 4 exists between two inflection points indicated by the maximum value 10 and the minimum value 11.

そこで、図５に示すように、このスリットの端部の位置を決定するために、出力電圧の分布曲線５の最大値１０と最小値１１との差から得られる差分電圧範囲Ｖｐ−ｐ１２に対して、プラスの偏曲点である最大値１０から数ｄＢ(図中では−ＸｄＢと表示してある。)低い閾値１３を出力電圧の分布曲線５のグラフに設定する。この設定は、表示装置がコンピュータの表示装置の場合には、表示装置の画面中のカーソルを用いてその画面内に描画する。出力電圧の分布曲線５の左側においても同様に、出力電圧の分布曲線５の最大値
１５と最小値１６の差から得られる差分電圧範囲Ｖｐ−ｐ１７に対して、プラスの偏曲点である最大値１５から数ｄＢ低い閾値１８を出力電圧の分布曲線５のグラフに設ける。出力電圧の分布曲線５上でこれらの閾値となる左右の２点１４と１９の間の距離を求めることで長さ精度を向上させることができる。この説明で、出力電圧の分布曲線５の左側とは、スリット４の左端寄りの出力分布を言い、出力電圧の分布曲線５の右側とは、スリット４の右端寄りの出力分布を言う。 Therefore, as shown in FIG. 5, in order to determine the position of the end of the slit, a difference voltage range Vp-p12 obtained from the difference between the maximum value 10 and the minimum value 11 of the output voltage distribution curve 5 is determined. Then, a threshold value 13 lower than the maximum value 10 which is a positive inflection point to a few dB (indicated in the figure as -X dB) is set in the graph of the distribution curve 5 of the output voltage. When the display device is a computer display device, this setting is drawn in the screen using a cursor in the screen of the display device. Similarly, on the left side of the output voltage distribution curve 5, the maximum is a positive deflection point with respect to the differential voltage range Vp−p 17 obtained from the difference between the maximum value 15 and the minimum value 16 of the output voltage distribution curve 5. A threshold 18 that is several dB lower than the value 15 is provided in the graph of the output voltage distribution curve 5. The length accuracy can be improved by obtaining the distance between the left and right two points 14 and 19 which are the threshold values on the distribution curve 5 of the output voltage. In this description, the left side of the output voltage distribution curve 5 refers to the output distribution near the left end of the slit 4, and the right side of the output voltage distribution curve 5 refers to the output distribution near the right end of the slit 4.

探傷プローブを白抜き矢印の方向へ移動（走査ともいう。）させ、その探傷プローブの移動位置ごとに、その位置の座標を記録し、且つその位置での出力電圧の値を記録しておく。このことで、２点１４と１９の位置の出力電圧値が測定された位置座標をその記録から割り出す。その２点１４と１９の位置座標が割り出せた後には、２点１４と１９の位置座標から２点１４と１９の間隔を算出してスリット４の長さと評価する。２点１４と１９の位置の出力電圧値が記録した出力電圧値の中に一致したものが無い場合には、その２点１４と１９の位置の出力電圧値に最も近い出力電圧値を示す位置座標を割り出し、その位置座標から２点１４と１９の間隔を算出してスリット４の長さと評価する。   The flaw detection probe is moved in the direction of the white arrow (also referred to as scanning), the coordinates of the position are recorded for each movement position of the flaw detection probe, and the value of the output voltage at that position is recorded. Thus, the position coordinates where the output voltage values at the positions of the two points 14 and 19 are measured are determined from the record. After the position coordinates of the two points 14 and 19 are determined, the distance between the two points 14 and 19 is calculated from the position coordinates of the two points 14 and 19, and the length of the slit 4 is evaluated. When the output voltage values at the positions of the two points 14 and 19 do not match the recorded output voltage values, the position indicating the output voltage value closest to the output voltage value at the positions of the two points 14 and 19 The coordinates are determined, the distance between the two points 14 and 19 is calculated from the position coordinates, and the length of the slit 4 is evaluated.

図６はスリット４の深さがスリット４の一端から他端にかけて徐々に変化する場合のスリット４の長さの評価について説明する図面である。この場合も図５の場合と同様に評価することで長さ評価が可能である。即ち、スリット４の端部の位置を決定するために、出力電圧の分布曲線５の最大値２１と最小値２２の差から得られる差分電圧範囲Ｖｐ−ｐ
２３に対して、プラスの偏曲点である最大値２１から数ｄＢ低い閾値２４を図６の下図のグラフ中に設ける。出力電圧の分布曲線５の左側も同様に、最大値２６と最小値２７の差から得られる差分電圧範囲Ｖｐ−ｐ２８に対して、プラスの偏曲点である最大値２６から数ｄＢ低い閾値２９をグラフ中に設ける。出力電圧の分布曲線５上でこれらの閾値となる左右の２点間２５と３０の距離を求めてスリット４の長さと評価し、長さの評価精度を向上させることができる。左右の２点間２５と３０の距離を求める方法は、図５の例と同様である。 FIG. 6 is a drawing for explaining the evaluation of the length of the slit 4 when the depth of the slit 4 gradually changes from one end to the other end of the slit 4. In this case, the length can be evaluated by evaluating in the same manner as in FIG. That is, in order to determine the position of the end of the slit 4, the differential voltage range Vp−p obtained from the difference between the maximum value 21 and the minimum value 22 of the output voltage distribution curve 5.
23, a threshold 24 that is a few dB lower than the maximum value 21 that is a positive inflection point is provided in the lower graph of FIG. Similarly, the left side of the output voltage distribution curve 5 has a threshold value 29 that is several dB lower than the maximum value 26, which is a positive inflection point, with respect to the differential voltage range Vp-p28 obtained from the difference between the maximum value 26 and the minimum value 27. Is provided in the graph. On the output voltage distribution curve 5, the distance between the left and right two points 25 and 30 serving as the threshold values is obtained and evaluated as the length of the slit 4, and the evaluation accuracy of the length can be improved. The method for obtaining the distance between the left and right two points 25 and 30 is the same as in the example of FIG.

図７もスリット４の一端から他端にかけて徐々に変化する場合のスリット４の長さの評価について説示する図面である。スリット４の深さの程度によっては、出力電圧の分布曲線５の右側にで最小値の偏曲点（マイナス側の偏曲点）が得られない。この場合のスリット４の長さ評価の方法を以下に説明する。上述の最小値の偏曲点がない場合は、最小値を無欠陥部の出力電圧値とする。無欠陥部の出力電圧値は、図７の下図のグラフ中で出力電圧の軸のグラフ原点（出力電圧のグラフ軸と位置のグラフ軸との交点）の電圧レベルを意味している。   FIG. 7 is also a drawing illustrating the evaluation of the length of the slit 4 when it gradually changes from one end to the other end of the slit 4. Depending on the depth of the slit 4, a minimum inflection point (minus-side inflection point) cannot be obtained on the right side of the output voltage distribution curve 5. A method for evaluating the length of the slit 4 in this case will be described below. When there is no inflection point having the minimum value, the minimum value is set as the output voltage value of the defect-free portion. The output voltage value of the defect-free portion means the voltage level of the graph origin of the output voltage axis (intersection of the output voltage graph axis and the position graph axis) in the lower graph of FIG.

出力電圧の分布曲線５からスリット４の右側の端部を決定するために、出力電圧の分布曲線５中のスリット４の右側の端部寄りの出力電圧の最大値３２と無欠陥部の出力電圧値の差から得られる差分電圧範囲Ｖｐ−ｐ３３に対して、プラスの偏曲点である最大値３２から数ｄＢ低い閾値３４を出力電圧の分布曲線５のグラフ中に設定する。   In order to determine the right end of the slit 4 from the output voltage distribution curve 5, the maximum value 32 of the output voltage near the right end of the slit 4 in the output voltage distribution curve 5 and the output voltage of the defect-free portion. A threshold 34 that is a few dB lower than the maximum value 32, which is a positive inflection point, is set in the graph of the output voltage distribution curve 5 with respect to the differential voltage range Vp-p33 obtained from the value difference.

出力電圧の分布曲線５からスリット４の左側の端部を決定するために、出力電圧の分布曲線５中のスリット４の左側の端部寄りの出力電圧の最大値３６と最小値３７の差から得られる差分電圧Ｖｐ−ｐ３８に対して、プラスの偏曲点である最大値３６から数ｄＢ低い閾値３９を出力電圧の分布曲線５のグラフ中に設定する。   In order to determine the left end of the slit 4 from the output voltage distribution curve 5, from the difference between the maximum value 36 and the minimum value 37 of the output voltage near the left end of the slit 4 in the output voltage distribution curve 5. A threshold 39 that is several dB lower than the maximum value 36, which is a positive inflection point, is set in the graph of the output voltage distribution curve 5 with respect to the obtained differential voltage Vp-p38.

出力電圧の分布曲線５上でこれらの閾値となる左右の２点間３５と４０の距離を求めてスリット４の長さと評価し、長さの評価精度を向上させることができる。左右の２点間
３５と４０の距離を求める方法は、図５の例と同様である。 On the output voltage distribution curve 5, the distance between the two left and right points 35 and 40, which are the threshold values, is obtained and evaluated as the length of the slit 4, thereby improving the length evaluation accuracy. The method for obtaining the distance between the left and right two points 35 and 40 is the same as in the example of FIG.

図８はスリット４の長さが短くて出力電圧の分布曲線５上の出力電圧の最大値４２が一つの場合のスリット４の長さの評価について説明する図である。この場合は、出力電圧の分布曲線５でスリットの右側端部を決定するために、出力電圧の分布曲線５上の最大値
４２と最小値４３の差から得られる差分電圧範囲Ｖｐ−ｐ４４に対して、プラスの偏曲点である最大値４２から数ｄＢ低い閾値４５を出力電圧の分布曲線５のグラフに設定する。出力電圧の分布曲線５でスリットの左側端部を決定するために、同様に、出力電圧の分布曲線５上の最大値４２と最小値４７の差から得られる差分電圧範囲Ｖｐ−ｐ４８に対して、プラスの偏曲点である最大値４２から数ｄＢ低い閾値４９を出力電圧の分布曲線５のグラフに設定する。 FIG. 8 is a diagram for explaining the evaluation of the length of the slit 4 when the length of the slit 4 is short and the maximum value 42 of the output voltage on the output voltage distribution curve 5 is one. In this case, in order to determine the right end of the slit in the output voltage distribution curve 5, the difference voltage range Vp−p 44 obtained from the difference between the maximum value 42 and the minimum value 43 on the output voltage distribution curve 5 is used. Thus, a threshold 45 that is several dB lower than the maximum value 42 that is a positive inflection point is set in the graph of the distribution curve 5 of the output voltage. In order to determine the left end of the slit in the output voltage distribution curve 5, similarly, with respect to the differential voltage range Vp−p 48 obtained from the difference between the maximum value 42 and the minimum value 47 on the output voltage distribution curve 5. A threshold 49 that is a few dB lower than the maximum value 42, which is a positive inflection point, is set in the graph of the distribution curve 5 of the output voltage.

出力電圧の分布曲線５上でこれらの閾値となる左右の２点間４６と５０の距離を求めてスリット４の長さと評価し、長さの評価精度を向上させることができる。左右の２点間
４６と５０の距離を求める方法は、図５の例と同様である。 On the output voltage distribution curve 5, the distance between the left and right two points 46 and 50, which are the threshold values, is obtained and evaluated as the length of the slit 4, and the length evaluation accuracy can be improved. The method for obtaining the distance between the left and right two points 46 and 50 is the same as in the example of FIG.

図９もスリット４の長さが短く出力電圧の分布曲線５における出力電圧の最大値５２が一つの場合の長さ評価について説明する図である。スリット４の深さの程度により、スリット４の右側寄りの位置で出力電圧の分布曲線５上に最小値の偏曲点が得られない場合におけるスリット４の長さの評価方法を図９に基づいて以下に説明する。   FIG. 9 is also a diagram illustrating length evaluation when the length of the slit 4 is short and the output voltage distribution curve 5 has one maximum output voltage value 52. A method for evaluating the length of the slit 4 when the minimum inflection point cannot be obtained on the distribution curve 5 of the output voltage at the position on the right side of the slit 4 depending on the depth of the slit 4 is shown in FIG. Will be described below.

図９の下図のグラフに見られるように、スリット４の右側寄りの位置で出力電圧の分布曲線５上に最小値の偏曲点がない場合は、その最小値を無欠陥部の出力電圧値とする。出力電圧の分布曲線５の出力電圧に基づいてスリット４の右側の端部の位置を決定するために、出力電圧の分布曲線５の最大値５２と無欠陥部の出力電圧値の差から得られる差分電圧範囲Ｖｐ−ｐ５３に対して、プラスの偏曲点である最大値５２から数ｄＢ低い閾値５４を出力電圧の分布曲線５のグラフに設定する。   As shown in the lower graph of FIG. 9, when there is no inflection point of the minimum value on the distribution curve 5 of the output voltage at the position on the right side of the slit 4, the minimum value is the output voltage value of the defect-free portion. And In order to determine the position of the right end of the slit 4 on the basis of the output voltage of the output voltage distribution curve 5, it is obtained from the difference between the maximum value 52 of the output voltage distribution curve 5 and the output voltage value of the defect-free portion. A threshold 54 that is several dB lower than the maximum value 52 that is a positive inflection point is set in the graph of the output voltage distribution curve 5 with respect to the differential voltage range Vp-p53.

出力電圧の分布曲線５に基づいてスリット４の左側の端部の位置を決定するために、出力電圧の分布曲線５の最大値５２とスリット４の左側よりの出力電圧の最小値５６との差から得られる差分電圧範囲Ｖｐ−ｐ５７に対して、プラスの偏曲点である最大値５２から数ｄＢ低い閾値５８を出力電圧の分布曲線５のグラフに設定する。   In order to determine the position of the left end of the slit 4 based on the output voltage distribution curve 5, the difference between the maximum value 52 of the output voltage distribution curve 5 and the minimum value 56 of the output voltage from the left side of the slit 4. A threshold 58 that is several dB lower than the maximum value 52 that is a positive inflection point is set in the graph of the distribution curve 5 of the output voltage with respect to the differential voltage range Vp−p57 obtained from the above.

出力電圧の分布曲線５上でこれらの閾値となる左右の２点間４６と５０の距離を求めてスリット４の長さと評価し、長さの評価精度を向上させることができる。左右の２点間
４６と５０の距離を求める方法は、図５の例と同様である。 On the output voltage distribution curve 5, the distance between the left and right two points 46 and 50, which are the threshold values, is obtained and evaluated as the length of the slit 4, and the length evaluation accuracy can be improved. The method for obtaining the distance between the left and right two points 46 and 50 is the same as in the example of FIG.

図１０は自然亀裂のように亀裂の深さが亀裂の長さ範囲内で何度も繰り返して変化するタイプの欠陥６０が金属製の試験体３に発生し、その亀裂、即ち欠陥６０の長さについて評価する例を説明する図である。この種欠陥６０もスリット４と同様に試験体の表面に開口している。したがって、以下の説明は、欠陥６０をスリット４と読み替えても同じである。   FIG. 10 shows that a defect 60 of a type in which the depth of the crack repeatedly changes within the crack length range, such as a natural crack, is generated in the metal specimen 3, and the crack, that is, the length of the defect 60 is shown. It is a figure explaining the example which evaluates about it. This kind of defect 60 is also opened on the surface of the test body in the same manner as the slit 4. Therefore, the following description is the same even if the defect 60 is read as the slit 4.

図１０の欠陥６０を渦電流探傷装置で測定すると、その出力電圧の分布曲線５は、図
１０の下図のグラフで示されるように、欠陥６０の左側寄りに出現する出力電圧の最大値６６と、同じく右側寄りに出現する出力電圧の最大値６１の範囲に、繰り返し凹凸の曲線成す出力電圧の分布曲線が出現する。このような場合も、図１０の欠陥６０の長さ評価するにあたって、欠陥６０の両端部の位置を決定するために、欠陥６０の左側寄りに出現する出力電圧の最大値６６と、同じく右側寄りに出現する出力電圧の最大値６１とを左右両側におけるプラスの偏曲点として利用する。 When the defect 60 shown in FIG. 10 is measured by an eddy current flaw detector, the distribution curve 5 of the output voltage shows the maximum value 66 of the output voltage appearing on the left side of the defect 60 as shown in the lower graph of FIG. Similarly, a distribution curve of the output voltage, which has a repetitive uneven curve, appears in the range of the maximum value 61 of the output voltage that appears on the right side. Also in such a case, in evaluating the length of the defect 60 in FIG. 10, in order to determine the positions of both ends of the defect 60, the maximum value 66 of the output voltage appearing on the left side of the defect 60 and the right side The maximum value 61 of the output voltage appearing at is used as a positive inflection point on both the left and right sides.

出力電圧の分布曲線５から欠陥６０の右側の端部位置を決定するために、最大値６１と最小値６２から得られるＶｐ−ｐ６３に対して、プラスの偏曲点６１から数ｄＢ低い閾値６４を設ける。欠陥６０の左側の端部位置を決定するために、同様に、最大値６６と最小値６７の差から得られる差分電圧範囲Ｖｐ−ｐ６８に対して、プラスの偏曲点６６から数ｄＢ低い閾値６９を設ける。出力電圧の分布曲線５上におけるこれらの閾値の２点間６５と７０の距離を求めることで長さ評価の精度を向上させることができる。その距離の求め方は図５の例と同じである。   In order to determine the right end position of the defect 60 from the distribution curve 5 of the output voltage, a threshold 64 that is several dB lower than the positive inflection point 61 with respect to Vp-p63 obtained from the maximum value 61 and the minimum value 62. Is provided. Similarly, in order to determine the left end position of the defect 60, a threshold voltage that is several dB lower than the positive inflection point 66 with respect to the differential voltage range Vp-p68 obtained from the difference between the maximum value 66 and the minimum value 67. 69 is provided. The accuracy of length evaluation can be improved by obtaining the distance between the two threshold values 65 and 70 on the output voltage distribution curve 5. The method for obtaining the distance is the same as in the example of FIG.

図１１は自然亀裂のように亀裂の深さが亀裂の長さ範囲内で何度も繰り返して変化するタイプの欠陥６０が金属製の試験体３に発生し、その亀裂、即ち欠陥６０の長さについて評価する例を説明する図である。この種欠陥６０もスリット４と同様に試験体の表面に開口している。図１０の例と異なる点は、出力電圧の分布曲線５の右側周辺の最小値を示す偏曲点がない場合の評価に対応していることである。   FIG. 11 shows that a defect 60 of a type in which the depth of the crack changes repeatedly within the length range of the crack, such as a natural crack, occurs in the metal specimen 3, and the crack, that is, the length of the defect 60. It is a figure explaining the example which evaluates about it. This kind of defect 60 is also opened on the surface of the test body in the same manner as the slit 4. The difference from the example of FIG. 10 is that the evaluation corresponds to the case where there is no inflection point indicating the minimum value around the right side of the distribution curve 5 of the output voltage.

即ち、最小値の偏曲点がない場合は、最小値を無欠陥部の出力電圧値とする。出力電圧の右側のスリット端部を決定するために、出力電圧の分布曲線５の右側の最大値７２と無欠陥部の出力電圧値の差から得られる差分電圧範囲Ｖｐ−ｐ７３に対して、プラスの偏曲点である最大値７２から数ｄＢ低い閾値７４を設ける。出力電圧の分布曲線５の左側は、最大値７６と最小値７７の差から得られる差分電圧範囲Ｖｐ−ｐ７８に対して、プラスの偏曲点である最大値７６から数ｄＢ低い閾値７９を設ける。   That is, when there is no minimum inflection point, the minimum value is set as the output voltage value of the defect-free portion. In order to determine the slit end portion on the right side of the output voltage, the difference voltage range Vp-p73 obtained from the difference between the maximum value 72 on the right side of the output voltage distribution curve 5 and the output voltage value of the defect-free portion is added. A threshold 74 that is several dB lower than the maximum value 72 that is the inflection point is provided. On the left side of the output voltage distribution curve 5, a threshold value 79 that is several dB lower than the maximum value 76, which is a positive inflection point, is provided with respect to the differential voltage range Vp−p 78 obtained from the difference between the maximum value 76 and the minimum value 77. .

出力電圧の分布曲線５上におけるこれらの閾値の２点間７５と８０の距離を求めることで長さ評価の精度を向上させることができる。その距離の求め方は図５の例と同じである。   The accuracy of length evaluation can be improved by obtaining the distance between the two points 75 and 80 of these threshold values on the distribution curve 5 of the output voltage. The method for obtaining the distance is the same as in the example of FIG.

図１２は自然亀裂のように亀裂の深さが亀裂の長さ範囲内で何度も繰り返して変化するタイプの欠陥６０が金属製の試験体３に発生し、その亀裂、即ち欠陥６０の長さについて評価する例を説明する図である。この種欠陥６０もスリット４と同様に試験体の表面に開口している。図１２の例は、出力電圧の分布曲線５に全体的に直流成分を含んでいる場合の長さ評価を説明するものである。   FIG. 12 shows that a defect 60 of a type in which the depth of the crack repeatedly changes within the length range of the crack, such as a natural crack, is generated in the metal specimen 3 and the length of the crack, that is, the length of the defect 60. It is a figure explaining the example which evaluates about it. This kind of defect 60 is also opened on the surface of the test body in the same manner as the slit 4. The example of FIG. 12 explains the length evaluation when the output voltage distribution curve 5 includes a direct current component as a whole.

出力電圧に直流成分を含んでいる場合もこれまでと同様に長さ評価が可能である。即ち、出力電圧の分布曲線５から右側のスリット端部の位置を決定するために、出力電圧の分布曲線５の右側の最大値８０と無欠陥部の出力電圧値との差から得られる差分電圧範囲
Ｖｐ−ｐ８１に対して、プラスの偏曲点である最大値８０から数ｄＢ低い閾値８２を設ける。出力電圧の左側は、最大値８４と最小値８５との差から得られる差分電圧範囲Ｖｐ−ｐ８６に対して、プラスの偏曲点である最大値８４から数ｄＢ低い閾値８７を設ける。出力電圧の分布曲線５上のこれらの閾値の２点間８３と８８の距離を求めることで長さ精度を向上させることができる。その距離の求め方は図５の例と同じである。 When the output voltage includes a DC component, the length can be evaluated as before. That is, in order to determine the position of the right slit end from the output voltage distribution curve 5, the differential voltage obtained from the difference between the maximum value 80 on the right side of the output voltage distribution curve 5 and the output voltage value of the defect-free portion. For the range Vp-p81, a threshold value 82 that is several dB lower than the maximum value 80, which is a positive inflection point, is provided. On the left side of the output voltage, a threshold value 87 that is several dB lower than the maximum value 84, which is a positive inflection point, is provided with respect to the differential voltage range Vp-p86 obtained from the difference between the maximum value 84 and the minimum value 85. The length accuracy can be improved by obtaining the distance between the two points 83 and 88 of these threshold values on the distribution curve 5 of the output voltage. The method for obtaining the distance is the same as in the example of FIG.

以上に示す閾値としては、１／２（−６ｄＢ）以下の値を利用することが望ましい。   As the threshold value shown above, it is desirable to use a value of 1/2 (−6 dB) or less.

図１３に本発明で評価したスリットの長さと実際のスリット長さとを比較した結果を示す。閾値には−１２ｄＢを利用した。実際のスリットの形状は、矩形と半だ円を用いた。本結果より、実際のスリットの長さと評価した長さは、よく一致しており、いずれの例も、同様な結果となり、本発明の評価方法の妥当性が確認できる。   FIG. 13 shows the result of comparing the slit length evaluated in the present invention with the actual slit length. A threshold of -12 dB was used. The actual slit shape was a rectangle and a semi-ellipse. From this result, the length of the actual slit and the evaluated length are in good agreement, and both examples have similar results, and the validity of the evaluation method of the present invention can be confirmed.

ここで、上記の実施例はスリット４を渦電流探傷法で探傷して得られるリサージュ波形をＹ軸に回転させ、Ｙ成分の出力電圧を利用した場合を示したが、スリット４を渦電流探傷法で探傷して得られるリサージュ波形をＸ軸に回転させ、Ｘ成分の出力電圧を利用した場合でも同様に評価可能である。   Here, the above embodiment shows the case where the Lissajous waveform obtained by flaw detection of the slit 4 by the eddy current flaw detection method is rotated about the Y axis, and the output voltage of the Y component is used. Evaluation is possible in the same manner even when the Lissajous waveform obtained by flaw detection by the method is rotated around the X axis and the output voltage of the X component is used.

図１に、本発明の長さ評価フロー図を示す。長さ評価は次の工程で可能となる。渦電流探傷装置の探傷プローブを被検査体上で移動（走査）させて、被検査体に対して渦電流探傷法を適用し、測定を開始１２１後、電流探傷装置の探傷プローブの各移動位置ごとに検出コイルからの電圧を渦電流探傷器に入力して検出コイルの基準電圧値に対する出力の変化を渦電流探傷器の出力電圧として検知して、各移動位置の位置座標上方とともにコンピュータに入力し、各移動位置に対する出力電圧のデータを作成し、そのデータに基づいて表示装置に出力電圧の分布曲線を表示する。このように出力電圧分布を測定する工程122の後に、工程１２２で得られた出力電圧の分布曲線５が図８や図９のように連続的な上に凸の分布を示す場合（プラス側に一つのピークとなる偏曲点を有する）は次を実施する。   FIG. 1 is a length evaluation flowchart of the present invention. Length evaluation is possible in the next step. The flaw detection probe of the eddy current flaw detection apparatus is moved (scanned) on the inspection object, the eddy current flaw detection method is applied to the inspection object, and the measurement is started 121. Each time the voltage from the detection coil is input to the eddy current flaw detector, the change in output relative to the reference voltage value of the detection coil is detected as the output voltage of the eddy current flaw detector, and input to the computer along with the position coordinates above each moving position. Then, output voltage data for each moving position is created, and an output voltage distribution curve is displayed on the display device based on the data. After the step 122 for measuring the output voltage distribution in this way, when the output voltage distribution curve 5 obtained in the step 122 shows a continuous upward convex distribution as shown in FIGS. Do one of the following:

即ち、出力電圧の分布曲線５の出力電圧の最大値を出力電圧のデータから例えばコンピュータの演算処理で抽出する工程１２３、出力電圧の分布曲線５にマイナス側の偏曲点を有する場合、この値を基準として、ない場合は無欠陥部の電圧値を基準として、電圧分布の最大値の１／２以下の任意の閾値を出力電圧の分布曲線５に対して、例えばコンピュータで設定する工程１２４、その閾値を越える断面距離またはその閾値と一致する出力電圧を示す探傷プローブの位置の２地点の距離を、例えばコンピュータで算出する工程１２５、以上で長さ評価を実施できる。   That is, when the maximum value of the output voltage of the output voltage distribution curve 5 is extracted from the output voltage data by, for example, a computer calculation process 123, this value is obtained when the output voltage distribution curve 5 has a negative inflection point. , With reference to the voltage value of the defect-free portion if not, a step 124 for setting an arbitrary threshold value equal to or less than ½ of the maximum value of the voltage distribution with respect to the output voltage distribution curve 5 by, for example, a computer, The length evaluation can be carried out in the above-described step 125, in which the distance between two points of the position of the flaw detection probe showing the cross-sectional distance exceeding the threshold value or the output voltage matching the threshold value is calculated by, for example, a computer.

一方、工程１２２で得られた出力電圧の分布曲線５が図１０，図１１，図１２のように不連続的な分布を有する場合（複数の偏曲点を有する）は次の工程を実施する。出力電圧の分布の周辺付近（欠陥の両端に相当する付近）に現れるプラスの偏曲点を、例えば出力電圧のデータからコンピュータで抽出する工程１２６、同じく出力電圧の分布の周辺付近にマイナス側の偏曲点を有する場合、この値を基準として、ない場合は無欠陥部の電圧値を基準として、プラスの偏曲点の出力電圧の１／２以下の任意の閾値を出力電圧の分布曲線５に対して、例えばコンピュータで設定する工程１２７、出力電圧の分布の周辺付近の閾値を越える断面距離またはその閾値を越える断面距離またはその閾値と一致する出力電圧を示す探傷プローブの位置の２地点の距離を、例えばコンピュータで算出する工程128、以上で長さ評価を実施できる。   On the other hand, when the output voltage distribution curve 5 obtained in step 122 has a discontinuous distribution (having a plurality of inflection points) as shown in FIGS. 10, 11, and 12, the following steps are performed. . A positive inflection point appearing in the vicinity of the periphery of the output voltage distribution (the vicinity corresponding to both ends of the defect) is extracted by, for example, a computer from the output voltage data 126, and the negative side is also near the periphery of the output voltage distribution. When there is an inflection point, with this value as a reference, when there is no inflection point, the voltage value of the defect-free portion is used as a reference, and an arbitrary threshold value less than or equal to 1/2 of the output voltage at the plus inflection point is set as the output voltage distribution curve 5 On the other hand, for example, in step 127 of setting by a computer, the cross-sectional distance exceeding the threshold value near the periphery of the output voltage distribution, the cross-sectional distance exceeding the threshold value, or the position of the flaw detection probe indicating the output voltage that matches the threshold value The length evaluation can be performed in the step 128 in which the distance is calculated by a computer, for example.

次に欠陥長さ評価が出来る装置の説明を記す。まず、渦電流探傷装置の渦電流プローブとしてマルチプローブの説明を行い、次にこのマルチプローブを利用した欠陥長さ評価が行える装置の説明をする。図１４は複数のコイルを利用したマルチプローブ９２を示している。マルチプローブ９２は一度の走査でコイル列の長さに対応する範囲を探傷することができるため、高速検査が可能となる。   Next, a description will be given of an apparatus capable of evaluating the defect length. First, a multiprobe will be described as an eddy current probe of an eddy current flaw detector, and then an apparatus capable of evaluating a defect length using the multiprobe will be described. FIG. 14 shows a multi-probe 92 using a plurality of coils. Since the multi-probe 92 can detect a range corresponding to the length of the coil array with a single scan, high-speed inspection is possible.

マルチプローブ９２は上述した渦電流プローブと同様に励磁コイル９０と検出コイル
９１があり、これを電子的にコイル列方向へ切り替えコイル列の長さに対応する範囲の探傷が可能となる。図中のコイル列方向に設けた複数の矢印は電子的な切り替え方向を示している。矢印の始点は励磁コイルを、終点は検出コイルを示し、１ｃｈからｎｃｈまでのコイル列に渡り電子的に切り替えることで、試験体３の表面に開口した欠陥９３の長さ方向、即ち欠陥の一端から他端方向へ一組の励磁コイルと検出コイルとを移動させたと同じ状況を作る。これで、コイル列の長さに対応する範囲で渦電流探傷法を試験体に対して実施する。この渦電流探傷法で各チャンネルの検出コイルからの誘起電力を渦電流探傷器に入力して各チャンネルの位置ごとの出力電圧を検知して出力電圧の分布曲線のデータを作成して表示装置に出力電圧の分布を表示する。 Similar to the eddy current probe described above, the multi-probe 92 includes an excitation coil 90 and a detection coil 91, which can be electronically switched in the coil array direction to perform flaw detection in a range corresponding to the length of the coil array. A plurality of arrows provided in the coil array direction in the drawing indicate the electronic switching direction. The starting point of the arrow indicates the excitation coil, and the end point indicates the detection coil. By electronically switching over the coil array from 1ch to nch, the length direction of the defect 93 opened on the surface of the test body 3, that is, one end of the defect. The same situation is created as when a pair of excitation coil and detection coil are moved in the direction from the other end to the other end. Thus, the eddy current flaw detection method is performed on the test specimen within a range corresponding to the length of the coil array. In this eddy current flaw detection method, the induced power from the detection coil of each channel is input to the eddy current flaw detector, the output voltage at each channel position is detected, and the distribution curve data of the output voltage is created and displayed on the display device. Display the output voltage distribution.

マルチプローブを利用した渦電流探傷装置を図１５に示す。図１５の渦電流探傷装置は上記したマルチプローブ９２を専用の渦電流探傷器９４に結線し、マルチプローブの一要素となる励磁コイルと検出コイルを電子的に切り替え、各ｃｈの出力電圧を表示することが出来る。例えば、図１５に示すように各コイルの出力電圧のデータ９６を基にして探傷領域を表示画面９５のように２次元的に表示する表示装置を渦電流探傷装置が有する。   An eddy current flaw detector using a multi-probe is shown in FIG. The eddy current flaw detector shown in FIG. 15 connects the above-described multi-probe 92 to a dedicated eddy-current flaw detector 94, electronically switches an excitation coil and a detection coil, which are elements of the multi-probe, and displays the output voltage of each channel. I can do it. For example, as shown in FIG. 15, the eddy current flaw detector has a display device that displays a flaw detection area two-dimensionally like a display screen 95 based on output voltage data 96 of each coil.

表示画面９５の内容では、欠陥の影響を受けた出力電圧の分布が漠然として判るがその分布から欠陥の長さを精度よく評価するには適さない。そこで、図１６に示した渦電流探傷装置は、欠陥の長さを精度よく評価するように構成されている。   In the content of the display screen 95, the distribution of the output voltage affected by the defect is vaguely understood, but it is not suitable for accurately evaluating the length of the defect from the distribution. Therefore, the eddy current flaw detector shown in FIG. 16 is configured to accurately evaluate the length of the defect.

即ち、図１６の渦電流探傷装置も図１５の渦電流探傷装置と同様に、渦電流探傷器がマルチプローブの各チャンネルの検出コイルから入力を受けると、渦電流探傷器は図１５の渦電流探傷装置と同様に各チャンネルごとに出力電圧のデータ９６を作って、コンピュータ１０４のメモリ（データ）９７へ電送する。メモリ（データ）９７内のデータ構成は、データ９６のように各チャンネルごとに且つマルチプローブ全体の各走査位置ごとに出力電圧のレベルが表示できる構成となっている。   That is, as in the eddy current flaw detector of FIG. 15, when the eddy current flaw detector receives an input from the detection coil of each channel of the multi-probe, the eddy current flaw detector of FIG. As with the flaw detector, output voltage data 96 is created for each channel and transmitted to the memory (data) 97 of the computer 104. The data configuration in the memory (data) 97 is configured such that the level of the output voltage can be displayed for each channel and for each scanning position of the entire multi-probe like the data 96.

渦電流探傷装置は、メモリ（データ）９７内のデータを用いて、コンピュータ１０４の表示部１０５に各ｃｈの２次元的な出力電圧分布の表示１０６、表示１０６の欠陥部に対応する出力電圧の分布曲線５の表示１０７，長さ評価結果１０８の表示を行うように構成される。   The eddy current flaw detector uses the data in the memory (data) 97 to display the two-dimensional output voltage distribution display 106 of each channel on the display unit 105 of the computer 104 and the output voltage corresponding to the defective part of the display 106. The distribution curve 5 is displayed 107 and the length evaluation result 108 is displayed.

これらの表示を可能とする渦電流探傷装置の構成部分について詳細を以下に示す。即ち、各チャンネルの位置座標データと紐付けしてた各コイルの出力電圧のデータ９６をメモリ（データ）９７に蓄積し、各ｃｈの代表値として最大値変位の絶対値をコンピュータ
１０４の演算部９８で算出し、プラスとマイナスの符号付でメモリ１００に蓄積する。このデータは、ｃｈ間距離を軸とした欠陥部に対応する出力電圧分布の表示１０７に利用する。次に、この出力電圧の周辺付近に現れるプラスの偏曲点部及び最小値をコンピュータ１０４の比較部９９で抽出し、これを利用して周辺付近の差分電圧範囲Ｖｐ−ｐをコンピュータ１０４で算出してメモリ１０１に蓄積する。別途、評価者は最大値の偏曲点からの閾値を入力部１０３からコンピュータ１０４に与える。この入力値を閾値として、メモリ１００に蓄積した各ｃｈの代表値（欠陥部に対応する出力電圧分布のデータ）とコンピュータ１０４で比較する。長さ評価結果１０８には、閾値と一致する２点の出力電圧のデータを選択してその選択したデータが有する位置座標情報を抽出し、２点の位置座標情報から２点の距離を演算する処理をコンピュータ１０４が実行し、その実行結果が２地点の距離として表示部１０５内の評価結果１０８に表示される。その表示部１０５に表示された表示１０７は出力電圧の分布曲線５を横軸に出力電圧レベルを、縦軸に各チャンネルの位置を採用して表示したものであり、１０９が欠陥の一方の端部よりの出力電圧の最小値
（マイナスの偏曲点）を、１１１が欠陥の他端の端部よりの出力電圧の最小値（マイナスの偏曲点）を、１１０が欠陥の一方の端部よりの出力電圧の最大値（プラスの偏曲点）を、１１２が欠陥の他端の端部よりの出力電圧の最大値（プラスの偏曲点）を表している。 Details of the components of the eddy current flaw detector that enable these displays will be described below. In other words, the output voltage data 96 of each coil linked to the position coordinate data of each channel is stored in the memory (data) 97, and the absolute value of the maximum displacement as the representative value of each channel is calculated by the computing unit of the computer 104. It is calculated at 98 and stored in the memory 100 with plus and minus signs. This data is used for the display 107 of the output voltage distribution corresponding to the defective portion with the inter-ch distance as an axis. Next, the positive inflection point and minimum value appearing near the periphery of the output voltage are extracted by the comparison unit 99 of the computer 104, and the difference voltage range Vp-p near the periphery is calculated by the computer 104 using this. And stored in the memory 101. Separately, the evaluator gives a threshold value from the maximum inflection point to the computer 104 from the input unit 103. Using this input value as a threshold value, the computer 104 compares the representative value of each channel stored in the memory 100 (output voltage distribution data corresponding to the defective portion). In the length evaluation result 108, the output voltage data of two points that match the threshold value are selected, the position coordinate information of the selected data is extracted, and the distance between the two points is calculated from the position coordinate information of the two points. The computer 104 executes the process, and the execution result is displayed on the evaluation result 108 in the display unit 105 as the distance between the two points. The display 107 displayed on the display unit 105 displays the output voltage distribution curve 5 by using the output voltage level on the horizontal axis and the position of each channel on the vertical axis, and 109 is one end of the defect. The minimum value of the output voltage from the part (negative inflection point), 111 the minimum value of the output voltage from the other end of the defect (negative inflection point), 110 the one end of the defect 112 represents the maximum value of the output voltage (plus inflection point), and 112 represents the maximum value (plus inflection point) of the output voltage from the end of the other end of the defect.

渦電流探傷法では、探傷プローブを構成している各コイルと被検査体の表面との間隔を一定に保つことがリフトオフノイズの低減に寄与して、亀裂の長さ評価に好結果をもたらす。そのため、探傷プローブとしてマルチプローブを採用した際のマルチプローブの試験体と各コイルまでの距離を一定に保つための機構を以下に説明する。   In the eddy current flaw detection method, keeping the distance between each coil constituting the flaw detection probe and the surface of the object to be inspected contributes to the reduction of lift-off noise and brings about a good result in the evaluation of the crack length. Therefore, a mechanism for keeping the distance between the multi-probe specimen and each coil constant when the multi-probe is used as a flaw detection probe will be described below.

マルチプローブの試験体と各コイルまでの距離を一定に保つための機構は、マルチプローブ９２の被検査体３との接触部が被検査体３に点接触する形状の複数の突起物に形成されている点に特徴的構成がある。   The mechanism for keeping the distance between the multi-probe test body and each coil constant is formed by a plurality of protrusions having a shape in which the contact portion of the multi-probe 92 with the test object 3 makes point contact with the test object 3. There is a characteristic configuration.

その構成によれば、マルチプローブ９２を図１４の白抜き矢印の方向へ走査しても、突起物が被検査体３の表面との間隔を一定の間隔に維持するので、リフトオフノイズが抑制できる。そのため、リフトオフノイズによるマルチプローブの探傷性能の低下が抑制できる。   According to the configuration, even when the multi-probe 92 is scanned in the direction of the white arrow in FIG. 14, the protrusion maintains a constant distance from the surface of the inspection object 3, so that lift-off noise can be suppressed. . Therefore, it is possible to suppress a decrease in the flaw detection performance of the multiprobe due to lift-off noise.

上記の特徴的構成を備えたマルチプローブの第１実施例は次のとおりである。即ち、図１７のように、屈曲性に富んで柔軟性のあるプラスチック製の基板２０１と、その基板
２０１の上面に固定された複数個の渦電流探傷用コイル２０２と、その基板２０１の下面に各渦電流探傷用コイル２０２の真下において形成された部分球面形状又は断面が逆三角形状の突起物２０４と、前記基板２０１にエッチングで高密度に配線した銅配線とから構成される。基板２０１としては、プラスチックの中でも耐熱性や機械的強度の良いポリイミド樹脂製のフィルム（フィルム厚が０.１５ミリ ）を用いることが好ましい。 A first embodiment of the multi-probe having the above-described characteristic configuration is as follows. That is, as shown in FIG. 17, a flexible and flexible plastic substrate 201, a plurality of eddy current flaw detection coils 202 fixed to the upper surface of the substrate 201, and a lower surface of the substrate 201 Each of the eddy current flaw detection coils 202 is composed of a protrusion 204 having a partially spherical shape or a cross-section of an inverted triangle formed immediately below each coil 202, and copper wiring that is densely wired on the substrate 201 by etching. As the substrate 201, it is preferable to use a polyimide resin film (film thickness is 0.15 mm) having good heat resistance and mechanical strength among plastics.

その渦電流探傷用コイル２０２とは、励磁コイル，検出コイル又は励磁・検出兼用コイルであり、それらのコイルには、銅配線が結線されて、マルチプローブ外の電源からコイルへ通電したり、コイルからの信号をマルチプローブに接続されている渦電流探傷装置の渦電流探傷器へと電送する際のマルチプローブ内での電送路として用いられる。   The eddy current flaw detection coil 202 is an excitation coil, a detection coil, or an excitation / detection coil, and these coils are connected to a copper wiring, and the coil is energized from a power source outside the multi-probe, Is used as an electric transmission path in the multi-probe when electric signals are transmitted to the eddy current flaw detector of the eddy current flaw detector connected to the multi-probe.

このような基板２０１は、屈曲性がよく被検査体の表面形状に沿って柔軟に変形するので、フレキシブルプリント基板と称せられ、フレキシブルプリント基板を採用したマルチプローブは基板がリジッドなものに比較して柔軟性があることからフレキシブル型マルチコイルＥＣＴプローブと称せられている。   Such a substrate 201 is flexible and deforms flexibly along the surface shape of the object to be inspected. Therefore, the substrate 201 is called a flexible printed circuit board, and a multi-probe using a flexible printed circuit board is compared with a rigid substrate. Because of its flexibility, it is called a flexible multi-coil ECT probe.

基板２０１は、成型用の金型にプラスチックを流し込む成型加工やプラスチック板を切削加工する方法などで製造される。基板２０１に装備される突起物２０４は、金型に突起物の型も加工しておき、その金型による成型加工によって、あるいは、プラスチック板から基板１を切削加工で製造する際に、突起物２０４も同時に切削加工で成型することによって基板２０１と一体に製造される。   The substrate 201 is manufactured by a molding process in which plastic is poured into a molding die or a method of cutting a plastic plate. The protrusions 204 provided on the substrate 201 are processed when the protrusions are processed into a mold and the substrate 1 is manufactured by molding using the mold or by cutting the substrate 1 from a plastic plate. 204 is also manufactured integrally with the substrate 201 by molding by cutting.

基板２０１内に銅配線を電気配線として施すことで、渦電流探傷用コイル２０２から直接的に電線をフレキシブル型マルチコイルＥＣＴプローブの外に引き出すものに比べてそのプローブの取扱い時の断線防止が可能となる。また、部分球面または逆三角形断面の突起物２０４を備えたことで突起物２０４を被検査体３の表面に接触させてそのプローブを走査するので、基板２０１の摩耗による基板２０１内の電気配線（銅配線）の断線を抑えることができる。更に、基板２０１に熱や触媒等で硬化する材料を用いてある場合には、基板２０１を作成した後に、突起物２０４を熱や触媒等で硬くすれば、基板２０１の耐摩耗性を向上し、フレキシブル型マルチコイルＥＣＴプローブの寿命を向上できる。   By providing copper wiring as electrical wiring in the substrate 201, it is possible to prevent disconnection during handling of the probe as compared to the case where the electric wire is directly drawn out of the flexible multi-coil ECT probe from the eddy current flaw detection coil 202. It becomes. Further, since the projection 204 is brought into contact with the surface of the object 3 to be inspected by providing the projection 204 having a partial spherical surface or an inverted triangular cross section, the wiring is scanned in the substrate 201 due to wear of the substrate 201 ( Disconnection of copper wiring) can be suppressed. Further, when the substrate 201 is made of a material that can be cured by heat, a catalyst, or the like, the wear resistance of the substrate 201 can be improved by making the protrusions 204 hard by heat, a catalyst, or the like after the substrate 201 is formed. The lifetime of the flexible multi-coil ECT probe can be improved.

突起物２０４は、図１７（ｄ）図のように球面の一部分を成す形状である部分球面形状と、図１７（ｅ）図のように突端を下方に向けた際に円錐や多角錐などの逆三角形の断面となる形状の例がかかげられるが、被検査体３の表面に点接触乃至は点接触に近い状態で接触する形状であればどの様な形状でも良い。いずれの場合も、渦電流探傷用コイル202の中心線２０５の延長上に突起物２０４の最突端部位が位置するように渦電流探傷用コイル２０２と突起物２０４との配置関係が整えられている。   As shown in FIG. 17 (d), the protrusion 204 has a partial spherical shape that is a part of a spherical surface, and a protrusion or a cone such as a cone or polygonal pyramid when the protrusion is directed downward as shown in FIG. 17 (e). Although an example of a shape having an inverted triangular cross section is used, any shape may be used as long as it is in contact with the surface of the inspection object 3 in a point contact state or a state close to a point contact. In any case, the arrangement relationship between the eddy current flaw detection coil 202 and the protrusion 204 is arranged so that the most protruding end portion of the protrusion 204 is positioned on the extension of the center line 205 of the eddy current flaw detection coil 202. .

この様なマルチプローブを渦電流探傷プローブとして用いれば、被検査体３の表面凹凸を有する曲面形状部であってもその部位の検査において、リフトオフによるノイズ信号が発生しない原理を以下に説明する。図２３のように、滑らかな曲面を表面６に有する被検査体３のその表面に対して、突起２０４の無いフレキシブル型マルチコイルＥＣＴプローブを探傷プローブとして適用して探傷した場合は、基板を被検査体３の表面に押し付けると、基板と被検査体との間に隙間が生じないので、フレキシブル型マルチコイルＥＣＴプローブをその表面に沿って走査しても、基板上に配置した渦電流探傷用コイルと被検査体の間隔（リフトオフ）が常に一定に保たれる。そのため、リストオフによるノイズ信号が発生しない探傷が可能である。   If such a multi-probe is used as an eddy current flaw detection probe, the principle that a noise signal due to lift-off does not occur in the inspection of the curved portion having the surface irregularities of the inspection object 3 will be described below. As shown in FIG. 23, when a flexible multi-coil ECT probe having no projection 204 is applied to the surface of the inspection object 3 having a smooth curved surface on the surface 6 as a flaw detection probe, the substrate is covered. When pressed against the surface of the inspection object 3, there is no gap between the substrate and the object to be inspected. Therefore, even if the flexible multi-coil ECT probe is scanned along the surface, it is used for eddy current flaw detection arranged on the substrate. The distance (lift-off) between the coil and the object to be inspected is always kept constant. Therefore, flaw detection can be performed without generating a noise signal due to wrist-off.

しかし、グラインダ等で被検査体３の表面２０６を研摩した後においては、その表面
２０６が図２３の中央の図のように凹凸状態となる。そのような凹凸状態では、局所的な表面凹凸により、基板上に配置した渦電流探傷用コイルと被検査体３の表面との間隔がフレキシブル型マルチコイルＥＣＴプローブを走査する際に変動する。そのため、リフトオフによるノイズ信号が発生し、探傷性能が悪化する等の問題が生じる。また、従来のフレキシブル型マルチコイルＥＣＴプローブでは、被検査体３と基板とが直接接触するため、フレキシブル型マルチコイルＥＣＴプローブを走査する際に基板が摩耗し、基盤内に施されている電気配線が断線する等の問題があった。 However, after the surface 206 of the object to be inspected 3 is polished by a grinder or the like, the surface 206 becomes uneven as shown in the center diagram of FIG. In such an uneven state, due to local surface unevenness, the distance between the eddy current flaw detection coil arranged on the substrate and the surface of the inspection object 3 varies when the flexible multi-coil ECT probe is scanned. For this reason, a noise signal is generated due to lift-off, and problems such as deterioration in flaw detection performance occur. Further, in the conventional flexible multi-coil ECT probe, since the object to be inspected 3 and the substrate are in direct contact, the substrate is worn when the flexible multi-coil ECT probe is scanned, and the electrical wiring provided in the substrate There was a problem such as disconnection.

一方、突起２０４を備えたフレキシブル型マルチコイルＥＣＴプローブでは、基板201の被検査体３の表面２０６との接触部に、部分球面状の突起物２０４を備えている。そのため、基板２０１を被検査体３の表面２０６に押し付けた際に突起物２０４が凸凹状の表面２０６に点接触して、基板２０１上に配置した渦電流探傷用コイル２０２と被検査体３の距離が突起物２０４で一定に保たれる。   On the other hand, the flexible multi-coil ECT probe provided with the protrusion 204 includes a partial spherical protrusion 204 at a contact portion of the substrate 201 with the surface 206 of the object 3 to be inspected. Therefore, when the substrate 201 is pressed against the surface 206 of the object to be inspected 3, the protrusion 204 comes into point contact with the uneven surface 206, and the eddy current flaw detection coil 202 disposed on the substrate 201 and the object 3 to be inspected. The distance is kept constant by the protrusion 204.

そのため、表面２０６が凹凸状態においても、渦電流探傷用コイル２０２と被検査体３の表面２０６との間の間隔がフレキシブル型マルチコイルＥＣＴプローブを走査した際にも変化せず、リフトオフの変動によるノイズ信号が渦電流探傷用コイル内に誘導されることは無く、リフトオフノイズの発生を抑制できる。   For this reason, even when the surface 206 is uneven, the distance between the eddy current flaw detection coil 202 and the surface 206 of the inspection object 3 does not change even when the flexible multi-coil ECT probe is scanned. The noise signal is not induced in the eddy current flaw detection coil, and the occurrence of lift-off noise can be suppressed.

また、突起物２０４が被検査体３に接触するので、フレキシブル型マルチコイルプローブの基板２０１に施されている電気配線にまで摩耗が進行するまでに従来よりも時間がかかり、断線防止事故にいたるまでのプローブ寿命が飛躍的に延命化できる。   In addition, since the protrusions 204 come into contact with the object to be inspected 3, it takes more time than before until the electrical wiring applied to the substrate 201 of the flexible type multi-coil probe progresses, leading to a disconnection prevention accident. Probe life can be dramatically extended.

フレキシブル型マルチコイルプローブに係る実施例２を、図１８に示す。実施例２は、既述の図１７（実施例１）のフレキシブル型マルチコイルプローブを改良したもので、改良内容を以下に解説し、その他の構成や作用は既述の実施例１と同じである。   A second embodiment of the flexible multi-coil probe is shown in FIG. Example 2 is an improvement on the flexible multi-coil probe shown in FIG. 17 (Example 1) described above. The details of the improvement will be described below, and other configurations and operations are the same as those of Example 1 described above. is there.

図２に示したフレキシブル型マルチコイルＥＣＴプローブの基板２０１は、表裏両面が平坦なフレキシブルプリント基板２０１に突起物２０４を機械的に固定したものである。突起物２０４は部分球面状あるいは逆三角形の断面を持つ形状を有し、材質は炭化ホウ素，工業用ダイヤモンド，工業用ルビー等の高硬度材料を採用している。その材料の硬度は被検査体３の表面２０６の硬度よりも高い硬度を示している。   A substrate 201 of the flexible multi-coil ECT probe shown in FIG. 2 is obtained by mechanically fixing a protrusion 204 to a flexible printed circuit board 201 having flat front and back surfaces. The protrusion 204 has a shape having a partial spherical shape or an inverted triangular cross-section, and a high-hardness material such as boron carbide, industrial diamond, or industrial ruby is adopted as the material. The hardness of the material is higher than the hardness of the surface 206 of the inspection object 3.

その突起物２０４は、図１８（ａ）（ｂ）（ｃ）（ｄ）（ｅ）（ｆ）のように、渦電流探傷用コイル２０２の中心線５の延長上に突起物２０４の最突端部位が位置するように渦電流探傷用コイル２０２と突起物２０４との配置関係が整えられている。このように配置された突起物２０４は、基板２０１に接着した複数層のプラスチック板２０８で突起物
２０４の周囲を基板２０１とで挟んで基板２０１に固定されている。プラスチック板208は基板２０１の柔軟性を損なわないように、及び突起物２０４の最突端部がプラスチック板２０８よりの外側に突き出るようにその厚さを配慮する。 As shown in FIGS. 18A, 18B, 18C, 18D, 18E, and 18F, the protrusion 204 is the most protruding end of the protrusion 204 on the extension of the center line 5 of the eddy current flaw detection coil 202. The positional relationship between the eddy current flaw detection coil 202 and the protrusion 204 is arranged so that the part is located. The protrusions 204 arranged in this way are fixed to the substrate 201 by sandwiching the periphery of the protrusions 204 with the substrate 201 with a plurality of layers of plastic plates 208 bonded to the substrate 201. The thickness of the plastic plate 208 is taken into consideration so as not to impair the flexibility of the substrate 201 and so that the most protruding end of the projection 204 protrudes outside the plastic plate 208.

そのほかの機械的固定方法としては、基板２０１に雌ネジ穴を開け、突起物２０４に加工した雄ネジをそのネジ穴に螺合させて基板２０１と突起物２０４とを固定する方法もある。   As another mechanical fixing method, there is also a method in which a female screw hole is formed in the substrate 201 and a male screw processed into a protrusion 204 is screwed into the screw hole to fix the substrate 201 and the protrusion 204.

フレキシブル型マルチコイルプローブに係る実施例３を、図１９に示す。実施例３は、既述の実施例１を改良したもので、改良内容を以下に解説し、その他の構成や作用は既述の実施例１と同じである。   A third embodiment of the flexible multi-coil probe is shown in FIG. The third embodiment is an improvement of the first embodiment described above. The details of the improvement will be described below, and the other configurations and operations are the same as those of the first embodiment described above.

図１９に示したフレキシブル型マルチコイルＥＣＴプローブの基板２０１は、表裏両面が平坦なフレキシブルプリント基板２０１に突起物２０４を接着剤２０９で固定したものである。突起物２０４は部分球面状あるいは断面が逆三角形の形状を有し、材質は炭化ホウ素，工業用ダイヤモンド，工業用ルビー等の高硬度材料を採用している。その材料の硬度は被検査体３の表面２０６の硬度よりも高い硬度を示している。   A substrate 201 of the flexible multi-coil ECT probe shown in FIG. 19 is obtained by fixing a projection 204 with an adhesive 209 on a flexible printed substrate 201 having flat front and back surfaces. The protrusion 204 has a partially spherical shape or a cross-section of an inverted triangle and is made of a high hardness material such as boron carbide, industrial diamond, or industrial ruby. The hardness of the material is higher than the hardness of the surface 206 of the inspection object 3.

その突起物２０４は、図１９（ａ）（ｂ）（ｃ）（ｄ）（ｅ）（ｆ）のように、渦電流探傷用コイル２０２の中心線２０５の延長上に突起物２０４の最突端部位が位置するように渦電流探傷用コイル２０２と突起物２０４との配置関係が整えられている。このように配置された突起物２０４は基板２０１に接着剤２０９で接着されて固定される。   As shown in FIGS. 19A, 19B, 19C, 19D, 19D, and 19F, the protrusion 204 is the most protruding end of the protrusion 204 on the extension of the center line 205 of the coil for eddy current testing 202. The positional relationship between the eddy current flaw detection coil 202 and the protrusion 204 is arranged so that the part is located. The protrusions 204 arranged in this way are bonded and fixed to the substrate 201 with an adhesive 209.

このタイプのフレキシブル型マルチコイルＥＣＴプローブは簡単に突起物２０４を取付けられるが、突起物２０４の脱落が問題となりそうな接着剤２０９の接着力低下を引き起こす環境で使用する場合は別の実施例１や実施例２の固定方法を採用した方がよい。   This type of flexible multi-coil ECT probe can be easily attached with the projection 204, but when used in an environment that causes a reduction in the adhesive strength of the adhesive 209, where the projection 204 may be a problem, another embodiment 1 It is better to adopt the fixing method of the second embodiment.

フレキシブル型マルチコイルプローブに係る第４実施例を図２０に示す。その第４実施例はコイル押付型マルチコイルＥＣＴプローブの例である。コイル押付型マルチコイル
ＥＣＴプローブのフレーム２１０には、図１８（ａ）（ｂ）（ｃ）のように、被検査体３の表面に対向する面に、複数のコイルホルダ２０３をフレーム２１０から突き出る方向へ進出したりフレーム２１０側へ戻る方向へ退避したり出来るようにされている。 FIG. 20 shows a fourth embodiment according to the flexible multi-coil probe. The fourth embodiment is an example of a coil pressing type multi-coil ECT probe. In the frame 210 of the coil pressing type multi-coil ECT probe, as shown in FIGS. 18A, 18B and 18C, a plurality of coil holders 203 protrude from the frame 210 on the surface facing the surface of the object 3 to be inspected. It can be advanced in the direction or retracted in the direction to return to the frame 210 side.

このような被検査体の方向へ進退自在にされているコイルホルダ２０３は次のようにしてフレーム２１０に装着される。このフレーム２１０は探傷作業中に被検査体側へ押しあてがわれても変形することの無い剛性を持たせてある。   The coil holder 203 that can be moved forward and backward in the direction of the object to be inspected is attached to the frame 210 as follows. The frame 210 has such rigidity that it will not be deformed even if it is pushed to the object side during the flaw detection operation.

即ち、フレーム２１０に形成されている開口２１１は、フレーム２１０の下面において狭い口径とされ、内側ではそれよりも広い口径とされている。その開口２１１の内側には、前記狭い開口よりも幅広なつば部２１２を有するコイルホルダ２０３が上下動自在に挿入され、その一部下部がフレーム２１０の下面から下方へ突き出ている。そのコイルホルダ２０３の上端部分と開口の上端部分との間にはコイルバネ２１３が設けられて、そのコイルバネ２１３が常にコイルホルダ２０３を開口２１１から突き出すようにコイルホルダ２０３にバネ力を加えている。   That is, the opening 211 formed in the frame 210 has a narrow diameter on the lower surface of the frame 210 and a larger diameter on the inside. Inside the opening 211, a coil holder 203 having a flange 212 wider than the narrow opening is inserted so as to be movable up and down, and a part of the lower part protrudes downward from the lower surface of the frame 210. A coil spring 213 is provided between the upper end portion of the coil holder 203 and the upper end portion of the opening, and the coil spring 213 applies a spring force to the coil holder 203 so that the coil holder 203 always protrudes from the opening 211.

開口から突き出されたコイルホルダ２０３の突端部は、図１８（ｄ）（ｆ）のような部分球面状または図１８（ｅ）（ｇ）のような円錐や多角錐などの突起端が下方に向けられた状態で逆三角形の断面形状を有する形状を有する突起物２０４として成型され、その突起物２０４がその最突端部で被検査体３の表面に点接触する形状とされている。   The protruding end of the coil holder 203 protruding from the opening has a partially spherical shape as shown in FIGS. 18D and 18F, or a protruding end such as a cone or a polygonal pyramid as shown in FIGS. 18E and 18G. The projection 204 is shaped as a projection 204 having an inverted triangular cross-sectional shape in the oriented state, and the projection 204 is in a shape that makes point contact with the surface of the inspection object 3 at its most projecting end.

コイルホルダ２０３の内側は、中空となっていて、その中には渦電流探傷用コイル202が内蔵され、渦電流探傷用コイル２０２の中心線２０５の延長線上に突起物２０４の最突端部が位置するように渦電流探傷用コイル２０２と突起物２０４との位置関係が配慮されている。渦電流探傷用コイル２０２には電気配線が結線され励磁用の電力や検出信号の伝送用に用いられる。このようにして、コイルホルダ２０３の先端に成型した突起物２０４は渦電流探傷用コイル２０２とコイルホルダ２０３を介して一体となっている。   The inside of the coil holder 203 is hollow, and an eddy current flaw detection coil 202 is housed therein, and the most protruding end portion of the projection 204 is positioned on the extension line of the center line 205 of the eddy current flaw detection coil 202. Thus, the positional relationship between the eddy current flaw detection coil 202 and the projection 204 is taken into consideration. An electric wiring is connected to the eddy current flaw detection coil 202, and it is used for transmitting excitation power and detection signals. Thus, the protrusion 204 molded at the tip of the coil holder 203 is integrated with the eddy current flaw detection coil 202 via the coil holder 203.

このようなコイル押付型マルチコイルＥＣＴプローブは、渦電流探傷用コイル２０２が渦電流探傷装置の渦電流探傷器や電源に接続されて用いられる。渦電流探傷を実施する際には、フレーム２１０を被検査体３の表面に向けて押すことによって、コイルホルダ203をその表面に押し付ける。その押し付けにより、被検査体３の表面に突起物２０４が点接触する。その被検査体３の表面が凹凸を有する場合には、凸部に接触した突起部が成型されているコイルホルダ２０３は、凹部に接触したコイルホルダ２０３よりも大きく開口
２１１内にコイルバネ２１３の力に逆らって押し入る。 Such a coil pressing type multi-coil ECT probe is used with an eddy current flaw detection coil 202 connected to an eddy current flaw detector or a power source of an eddy current flaw detector. When performing eddy current flaw detection, the coil holder 203 is pressed against the surface of the object 3 by pressing the frame 210 toward the surface of the inspection object 3. By the pressing, the protrusion 204 is brought into point contact with the surface of the inspection object 3. When the surface of the object to be inspected 3 has irregularities, the coil holder 203 in which the protrusions that are in contact with the protrusions are molded is larger than the coil holder 203 that is in contact with the recesses, and the force of the coil spring 213 is within the opening 211. Push in against.

このようにして、その凹凸によって各コイルホルダ２０３の開口２１１内への押し入り寸法が相違しますが、その押し入り動作には、渦電流探傷用コイル２０２がコイルホルダ２０３と同量だけ押し入れ方向に移動しますので、渦電流探傷用コイル２０２と被検査体３の表面との間隔（リフトオフ量）は一定に保たれます。そのため、リフトオフノイズの発生を抑制することが出来ます。   In this way, the indentation dimensions of the coil holders 203 into the openings 211 differ depending on the unevenness, but the eddy current flaw detection coil 202 moves in the indentation direction by the same amount as the coil holder 203 in the indentation operation. Therefore, the distance (lift-off amount) between the eddy current testing coil 202 and the surface of the inspection object 3 is kept constant. Therefore, the occurrence of lift-off noise can be suppressed.

コイル押付型マルチコイルＥＣＴプローブを走査して検査位置を被検査体３の表面に沿って移動させても、渦電流探傷用コイル２０２と被検査体３の表面との間隔（リフトオフ量）は一定に保たれますので、リフトオフノイズの発生を抑制することが出来ます。   Even when the coil pressing type multi-coil ECT probe is scanned and the inspection position is moved along the surface of the inspection object 3, the distance (lift-off amount) between the eddy current flaw detection coil 202 and the surface of the inspection object 3 is constant. Therefore, the lift-off noise can be suppressed.

図２０の例ではコイルバネ２１３をコイルホルダ２０３のサスペンションとして用いて検査表面の凹凸に追従させたが、コイルバネ２１３の代わりにガス圧，水圧，油圧を用いたシリンダ装置でコイルホルダ２０３のサスペンションを構成しても良い。また、ゴム等の弾性体の中にコイルホルダ２０３を抜けないように埋め込み、その弾性体の弾性力を利用してコイルホルダ２０３をサスペンスしてもよい。   In the example of FIG. 20, the coil spring 213 is used as a suspension of the coil holder 203 to follow the unevenness on the inspection surface. You may do it. Alternatively, the coil holder 203 may be embedded in an elastic body such as rubber so as not to come out, and the coil holder 203 may be suspended using the elastic force of the elastic body.

コイル押付型マルチコイルＥＣＴプローブを走査する際に、コイルホルダ２０３と同材質の突起物２０４の摩耗が問題となる場合は、コイルホルダや突起物２０４の材料として熱硬化性プラスチックを採用して、少なくとも突起物２０４を熱硬化により耐摩耗性を向上できる。   When scanning the coil pressing type multi-coil ECT probe, if wear of the projections 204 made of the same material as the coil holder 203 becomes a problem, a thermosetting plastic is used as the material of the coil holder or projections 204, At least the protrusion 204 can be improved in wear resistance by thermosetting.

フレキシブル型マルチコイルプローブに係る第５実施例を図２１に示した。図２１の第５実施例は、既述の第４実施例のコイル押付型マルチコイルＥＣＴプローブを改良した例である。改良内容を以下に説明し、ここで説明しない構成や作用は第４実施例と同じなのでその説明を省略する。即ち、改良点は、コイルホルダ２０３と突起物２０４とを別々に作成し、コイルホルダ２０３の端部に突起物２０４をはめ込むことで機械的にコイルホルダ２０３と突起物２０４を一体化する。   FIG. 21 shows a fifth embodiment relating to the flexible multi-coil probe. The fifth embodiment of FIG. 21 is an example in which the coil pressing type multi-coil ECT probe of the fourth embodiment described above is improved. The details of the improvement will be described below. Since the configuration and operation not described here are the same as those in the fourth embodiment, description thereof will be omitted. That is, the improvement is that the coil holder 203 and the projection 204 are separately formed, and the projection 204 is fitted into the end of the coil holder 203 so that the coil holder 203 and the projection 204 are mechanically integrated.

その一体化のために、コイルホルダ２０３の端部には逆ハの字型の断面を有する孔214を加工しておく。その孔２１４には、図２１（ｄ）（ｅ）（ｆ）（ｇ）のように、突起物２０４をはめ込んで、突起物２０４の突端はコイルホルダ２０３から突き出しておく。   For the integration, a hole 214 having an inverted cross section is processed at the end of the coil holder 203. As shown in FIGS. 21D, 21E, 21F, and 21G, the protrusion 204 is fitted into the hole 214, and the protruding end of the protrusion 204 protrudes from the coil holder 203.

突起物２０４の摩耗が問題となる場合は、突起物２０４の材料として、炭化ホウ素，工業用ダイヤモンド，工業用ルビー等の高硬度材料を採用することで耐摩耗性の問題は解決する。このように、突起物２０４の材料をコイルホルダ２０３の材料とは相違する材料に選択して、必要に応じた材料が選択できる。   When wear of the protrusions 204 becomes a problem, the problem of wear resistance is solved by adopting a high-hardness material such as boron carbide, industrial diamond, or industrial ruby as the material of the protrusions 204. Thus, the material of the protrusion 204 can be selected as a material different from the material of the coil holder 203, and the material according to need can be selected.

フレキシブル型マルチコイルプローブに係る第６実施例を図２２に示した。第６実施例は、既述の第４実施例のコイル押付型マルチコイルＥＣＴプローブを改良した例である。改良内容を以下に説明し、ここで説明しない構成や作用は第４実施例と同じなのでその説明を省略する。即ち、改良点は、コイルホルダ２０３と突起物２０４とを別々に作成し、図２１（ｄ）（ｅ）（ｆ）（ｇ）のように、コイルホルダ２０３の端部に突起物２０４を接着剤２０９で接着してコイルホルダ２０３と突起物２０４を一体化する。   FIG. 22 shows a sixth embodiment related to the flexible multi-coil probe. The sixth embodiment is an example in which the coil pressing type multi-coil ECT probe of the above-described fourth embodiment is improved. The details of the improvement will be described below. Since the configuration and operation not described here are the same as those in the fourth embodiment, description thereof will be omitted. That is, the improvement is that the coil holder 203 and the projection 204 are separately formed, and the projection 204 is bonded to the end of the coil holder 203 as shown in FIGS. 21 (d) (e) (f) (g). The coil holder 203 and the projection 204 are integrated by bonding with the agent 209.

突起物２０４の摩耗が問題となる場合は、突起物２０４の材料として、炭化ホウ素，工業用ダイヤモンド，工業用ルビー等の高硬度材料を採用することで耐摩耗性の問題は解決する。このように、突起物２０４の材料をコイルホルダ２０３の材料とは相違する材料に選択して、必要に応じた材料が選択できる。   When wear of the protrusions 204 becomes a problem, the problem of wear resistance is solved by adopting a high-hardness material such as boron carbide, industrial diamond, or industrial ruby as the material of the protrusions 204. Thus, the material of the protrusion 204 can be selected as a material different from the material of the coil holder 203, and the material according to need can be selected.

このタイプのコイル押付型マルチコイルＥＣＴプローブは簡単に突起物２０４をコイルホルダ２０３に取付けられるが、突起物２０４の脱落が問題となりそうな環境で使用する場合は第４実施例や第５実施例のような別の固定方法を突起物２０４をコイルホルダ203へ固定する方法として採用することが好ましい。   In this type of coil pressing type multi-coil ECT probe, the projection 204 can be easily attached to the coil holder 203. However, when the projection 204 is used in an environment where the projection 204 may be a problem, the fourth and fifth embodiments are used. It is preferable to adopt another fixing method as described above as a method of fixing the protrusion 204 to the coil holder 203.

渦電流探傷用コイル２０２の配置は、図１７から図２２に見受けられるように、千鳥配置でもよく正方格子配置でもかまわない。   The arrangement of the eddy current flaw detection coil 202 may be a staggered arrangement or a square lattice arrangement, as can be seen in FIGS.

図１７から図２２に示したいずれかのマルチプローブを渦電流探傷器９４に接続して渦電流探傷法の実施に用いれば、被検査体３の表面が平坦でなくともリフトオフノイズの悪影響を受けずに渦電流探傷結果や欠陥長さの評価が達成できる。   If any of the multi-probes shown in FIGS. 17 to 22 is connected to the eddy current flaw detector 94 and used for carrying out the eddy current flaw detection method, even if the surface of the inspection object 3 is not flat, it is adversely affected by lift-off noise. Therefore, the evaluation of the eddy current inspection result and the defect length can be achieved.

図１７から図２２に示した各マルチプローブに基づいて以下のような提案が出来る。即ち、基板と、前記基板の一方の面に設けられた複数個の渦電流探傷用コイルと、前記一方の面とは反対の位置に面する前記基板の他方の面に、前記渦電流探傷用コイルの中心線延長上に設けられた複数個の突起物とを備えている渦電流探傷用マルチコイルプローブを第１の提案として提案できる。   The following proposals can be made based on the multiprobes shown in FIGS. That is, the substrate, a plurality of eddy current flaw detection coils provided on one surface of the substrate, and the eddy current flaw detection on the other surface of the substrate facing a position opposite to the one surface. A multi-coil probe for eddy current testing comprising a plurality of protrusions provided on the extension of the center line of the coil can be proposed as a first proposal.

さらには、その第１の提案において、前記基板は前記渦電流探傷用コイルと結線された電気配線が施されているフレキシブルプリント基板である渦電流探傷用マルチコイルプローブを第２の提案として提案できる。   Furthermore, in the first proposal, a multi-coil probe for eddy current testing can be proposed as a second proposal in which the substrate is a flexible printed circuit board provided with electrical wiring connected to the eddy current testing coil. .

また、フレームと、前記フレームに被検査体の方向へ進退自在に設けられた複数個の渦電流探傷用コイルと、前記渦電流探傷用コイルの前記被検査体に面する側に配置されて前記コイルと一体にされている複数個の突起物とを備えている渦電流探傷用マルチコイルプローブを第３の提案として提案できる。   And a frame, a plurality of eddy current flaw detection coils provided on the frame so as to be able to advance and retreat in the direction of the object to be inspected, and the eddy current flaw detection coil disposed on the side facing the object to be inspected. A multi-coil probe for eddy current flaw detection provided with a plurality of protrusions integrated with a coil can be proposed as a third proposal.

更には、第１の提案から第３の提案のいずれかの提案において、前記突起物の硬度は、前記被検査体の硬度以上とされている渦電流探傷用マルチコイルプローブが第４の提案として提案できる。   Furthermore, in any one of the first to third proposals, a eddy current flaw detection multi-coil probe in which the hardness of the protrusion is equal to or higher than the hardness of the object to be inspected is a fourth proposal. Can make a suggestion.

更には、第１の提案から第４の提案のいずれかの提案において、前記突起物の前記被検査体側の部分は突起端を下方に向けた際に部分球面状又は逆三角形の断面を有する形状に形成されている渦電流探傷用マルチコイルプローブが提案できる。   Further, in any one of the first to fourth proposals, the portion of the protrusion on the side of the object to be inspected has a shape having a partial spherical surface or an inverted triangular cross section when the protrusion end faces downward. It is possible to propose a multi-coil probe for eddy current flaws formed on the surface.

本発明は、渦電流探傷法による非破壊検査を実施する渦電流探傷装置に利用される。   The present invention is used in an eddy current flaw detection apparatus that performs nondestructive inspection by an eddy current flaw detection method.

本発明の欠陥長さ評価方法に関する説明図である。It is explanatory drawing regarding the defect length evaluation method of this invention. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流探傷コイルと金属製試験体の配置図。Arrangement diagram of eddy current testing coil and metal specimen. コイルが作る渦電流分布の説明図である。It is explanatory drawing of the eddy current distribution which a coil produces. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 渦電流プローブによる出力電圧分布の説明図である。It is explanatory drawing of the output voltage distribution by an eddy current probe. 本発明による欠陥長さ評価の実験結果の説明図である。It is explanatory drawing of the experimental result of defect length evaluation by this invention. 本発明の渦電流探傷装置に利用するプローブの説明図である。It is explanatory drawing of the probe utilized for the eddy current flaw detector of this invention. 従来の渦電流探傷装置の説明図である。It is explanatory drawing of the conventional eddy current flaw detector. 本発明の渦電流探傷装置の説明図である。It is explanatory drawing of the eddy current flaw detector of this invention. フレキシブル型マルチコイルＥＣＴプローブの第１実施例にを示す図にして、（ａ）図はそのプローブの立面図、（ｂ）図はそのプローブの下面図、（ｃ）図はそのプローブの右側面図、（ｄ）図は部分球面状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｅ）図は錘状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｆ）図は（ｄ）図の丸印で囲った部位の拡大断面図、（ｇ）図は（ｅ）図の丸印で囲った部位の拡大断面図である。FIG. 2 is a diagram showing a first embodiment of a flexible multi-coil ECT probe, where (a) is an elevation view of the probe, (b) is a bottom view of the probe, and (c) is a right side of the probe. FIG. 4D is a cross-sectional view of the probe taken along line aa when a partially spherical protrusion is used, and FIG. 5E is a cross-sectional view along line aa of the probe when a weight-like protrusion is used. FIG. 5 (f) is an enlarged cross-sectional view of a portion surrounded by a circle in FIG. 4 (d), and FIG. 5 (g) is an enlarged cross-sectional view of a portion surrounded by the circle in FIG. フレキシブル型マルチコイルＥＣＴプローブの第２実施例示す図にして、（ａ）図はそのプローブの立面図、（ｂ）図はそのプローブの下面図、（ｃ）図はそのプローブの右側面図、（ｄ）図は部分球面状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｅ）図は錘状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｆ）図は（ｄ）図の丸印で囲った部位の拡大断面図、（ｇ）図は（ｅ）図の丸印で囲った部位の拡大断面図である。FIG. 2 is a diagram showing a second embodiment of the flexible multi-coil ECT probe, wherein FIG. 5A is an elevation view of the probe, FIG. 5B is a bottom view of the probe, and FIG. (D) is an aa cross-sectional view of the probe when a partially spherical protrusion is used, and (e) is an aa cross-sectional view of the probe when a weight-like protrusion is used, (F) The figure is an expanded sectional view of the part enclosed by the circle mark of (d) figure, (g) Drawing is the expanded sectional view of the part enclosed by the circle mark of (e) figure. フレキシブル型マルチコイルＥＣＴプローブの第３実施例を示す図にして、（ａ）図はそのプローブの立面図、（ｂ）図はそのプローブの下面図、（ｃ）図はそのプローブの右側面図、（ｄ）図は部分球面状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｅ）図は錘状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｆ）図は（ｄ）図の丸印で囲った部位の拡大断面図、（ｇ）図は（ｅ）図の丸印で囲った部位の拡大断面図である。FIG. 10 is a diagram showing a third embodiment of the flexible type multi-coil ECT probe, where (a) is an elevational view of the probe, (b) is a bottom view of the probe, and (c) is a right side of the probe. FIG. 4D is a cross-sectional view of the probe taken along line aa when a partially spherical protrusion is used. FIG. 5E is a cross-sectional view of the probe taken along line aa when a weight-like protrusion is used. (F) The figure is an expanded sectional view of the part enclosed with the circle of (d) figure, (g) Drawing is the expanded sectional view of the part enclosed with the circle of (e) figure. コイル押付型マルチコイルＥＣＴプローブの第４実施例を示す図にして、（ａ）図はそのプローブの立面図、（ｂ）図はそのプローブの下面図、（ｃ）図はそのプローブの右側面図、（ｄ）図は部分球面状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｅ）図は錘状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｆ）図は（ｄ）図の丸印で囲った部位の拡大断面図、（ｇ）図は（ｅ）図の丸印で囲った部位の拡大断面図である。The figure shows a fourth embodiment of the coil pressing type multi-coil ECT probe, wherein (a) is an elevation view of the probe, (b) is a bottom view of the probe, and (c) is a right side of the probe. FIG. 4D is a cross-sectional view of the probe taken along line aa when a partially spherical protrusion is used, and FIG. 5E is a cross-sectional view along line aa of the probe when a weight-like protrusion is used. FIG. 5 (f) is an enlarged cross-sectional view of a portion surrounded by a circle in FIG. 4 (d), and FIG. 5 (g) is an enlarged cross-sectional view of a portion surrounded by the circle in FIG. コイル押付型マルチコイルＥＣＴプローブの第５実施例を示す図にして、（ａ）図はそのプローブの立面図、（ｂ）図はそのプローブの下面図、（ｃ）図はそのプローブの右側面図、（ｄ）図は部分球面状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｅ）図は錘状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｆ）図は（ｄ）図の丸印で囲った部位の拡大断面図、（ｇ）図は（ｅ）図の丸印で囲った部位の拡大断面図である。The figure shows a fifth embodiment of the coil pressing type multi-coil ECT probe, wherein (a) is an elevation view of the probe, (b) is a bottom view of the probe, and (c) is a right side of the probe. FIG. 4D is a cross-sectional view of the probe taken along line aa when a partially spherical protrusion is used, and FIG. 5E is a cross-sectional view along line aa of the probe when a weight-like protrusion is used. FIG. 5 (f) is an enlarged cross-sectional view of a portion surrounded by a circle in FIG. 4 (d), and FIG. 5 (g) is an enlarged cross-sectional view of a portion surrounded by the circle in FIG. コイル押付型マルチコイルＥＣＴプローブの第６実施例を示す図にして、（ａ）図はそのプローブの立面図、（ｂ）図はそのプローブの下面図、（ｃ）図はそのプローブの右側面図、（ｄ）図は部分球面状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｅ）図は錘状の突起物を用いた場合のそのプローブのａ−ａ断面図、（ｆ）図は（ｄ）図の丸印で囲った部位の拡大断面図、（ｇ）図は（ｅ）図の丸印で囲った部位の拡大断面図である。The figure shows a sixth embodiment of the coil pressing type multi-coil ECT probe, where (a) is an elevation view of the probe, (b) is a bottom view of the probe, and (c) is a right side of the probe. FIG. 4D is a cross-sectional view of the probe taken along line aa when a partially spherical protrusion is used, and FIG. 5E is a cross-sectional view along line aa of the probe when a weight-like protrusion is used. FIG. 5 (f) is an enlarged cross-sectional view of a portion surrounded by a circle in FIG. 4 (d), and FIG. 5 (g) is an enlarged cross-sectional view of a portion surrounded by the circle in FIG. 従来例と本発明の実施例によるフレキシブル型マルチコイルＥＣＴプローブを表面凹凸を有する被検査体の曲面部にそのプローブをあてがった状態を説明する図である。It is a figure explaining the state which applied the probe to the curved-surface part of the to-be-inspected object which has a surface unevenness | corrugation in the flexible type multi-coil ECT probe by the prior art example and the Example of this invention.

符号の説明Explanation of symbols

１…励磁コイル、２…検出コイル、３…試験体（被検査体とも言う）、１０…プラス側の偏曲点（最大値とも言う。）、１１…マイナス側の偏曲点（最小値とも言う。）、１２…差分電圧範囲Ｖｐ−ｐ、１３…閾値。

DESCRIPTION OF SYMBOLS 1 ... Excitation coil, 2 ... Detection coil, 3 ... Test body (also called to-be-inspected object), 10 ... Positive side inflection point (also called maximum value), 11 ... Negative side inflection point (both minimum value) 12) Differential voltage range Vp-p, 13 ... Threshold.

Claims (7)

渦電流探傷法による表面欠陥の検査において、表面欠陥による出力電圧の分布を用いて、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法。   A surface defect length evaluation method characterized in that, in an inspection of a surface defect by an eddy current flaw detection method, an existence range of a surface defect or an opening length of the defect is evaluated using a distribution of an output voltage due to the surface defect. 請求項１において、表面スリットを探傷した時の出力電圧が実質的にリサージュ波形のＸ軸またはＹ軸方向のいずれかに出力する条件に設定し、表面欠陥を探傷した時に得られる設定した軸成分の出力電圧が、連続的な上に凸の分布をもつ場合は出力電圧の最大値を利用し、また、出力分布が不連続的な分布をもつ場合は出力分布の周辺付近に現れる偏曲点を利用して、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法。   2. The set axial component obtained when a surface defect is detected by setting the condition that the output voltage when the surface slit is detected is substantially output in either the X-axis or Y-axis direction of the Lissajous waveform. When the output voltage of has a continuous upward convex distribution, the maximum value of the output voltage is used, and when the output distribution has a discontinuous distribution, the inflection point appears near the periphery of the output distribution. A surface defect length evaluation method characterized by evaluating the existence range of surface defects or the opening length of defects using 請求項２において、設定した軸成分の出力電圧が連続的な上に凸の分布をもつ場合、無欠陥領域の出力電圧を基準とし、その基準と出力電圧の最大値と１／２以下の任意の閾値で切った出力電圧分布の断面あるいは線から、また、出力分布が不連続的な分布をもつ場合、無欠陥領域の出力電圧を基準とし、その基準と出力分布の周辺付近に現れるプラスの偏曲点の出力電圧の１／２以下の任意の閾値で切った出力電圧分布の断面あるいは線から、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法。   3. When the set output voltage of the axial component has a continuous upward convex distribution, the output voltage in the defect-free region is used as a reference, the reference and the maximum value of the output voltage, and an arbitrary value less than 1/2 If the output distribution has a discontinuous distribution or a section or line of the output voltage distribution cut at the threshold value, the output voltage in the defect-free area is used as a reference, and the positive voltage that appears in the vicinity of the reference and the output distribution The surface defect length is characterized by evaluating the existence range of surface defects or the opening length of the defects from the cross section or line of the output voltage distribution cut at an arbitrary threshold value less than or equal to 1/2 of the output voltage at the inflection point. Evaluation methods. 前記請求項３において、出力分布の周辺付近にプラスとマイナスの偏曲点の対が現れる場合は、マイナスの偏曲点の出力電圧を基準とし、その基準とプラスの偏曲点の出力電圧の１／２以下の任意の閾値で切った出力電圧分布の断面あるいは線から、表面欠陥の存在範囲または欠陥の開口長さを評価することを特徴とする表面欠陥長さ評価方法。   In claim 3, when a pair of positive and negative inflection points appears near the periphery of the output distribution, the output voltage of the negative inflection point is used as a reference, and the output voltage of the reference and the positive inflection point is A surface defect length evaluation method comprising evaluating a surface defect existence range or a defect opening length from a cross section or a line of an output voltage distribution cut at an arbitrary threshold value of 1/2 or less. 渦電流探傷法による表面欠陥の検査装置において、連続的な上に凸の分布をもつ場合は出力電圧の最大値、また、出力分布が不連続的な分布をもつ場合は出力分布の周辺付近に現れる偏曲点を利用して電圧最大変位を求める手段と、出力分布と入力部からの閾値とを比較し、閾値を越える断面距離または２地点の距離を算出する手段と、該距離を表示する表示部を有することを特徴とする渦電流探傷装置。   In the surface defect inspection system using the eddy current flaw detection method, the maximum value of the output voltage is obtained when the convex distribution is continuous and the output distribution is discontinuous. Means for obtaining the maximum voltage displacement using the appearing inflection point, means for comparing the output distribution with the threshold value from the input unit, calculating the cross-sectional distance exceeding the threshold value or the distance between the two points, and displaying the distance An eddy current flaw detector having a display unit. 被検体の表面欠陥を検査する渦電流探傷法において、該表面欠陥による出力電圧の分布に基づき、該表面欠陥の存在範囲または欠陥の開口長さを検査することを特徴とする渦電流探傷法。   In an eddy current flaw detection method for inspecting a surface defect of a subject, an eddy current flaw detection method is characterized in that the existence range of the surface defect or the opening length of the defect is inspected based on an output voltage distribution due to the surface defect. 被検体の表面欠陥を検査する渦電流探傷装置において、該表面欠陥による出力電圧の分布に基づき該表面欠陥の存在範囲または欠陥の開口長さを算出する手段を備えたことを特徴とする渦電流探傷装置。

An eddy current flaw detector for inspecting a surface defect of an object, comprising: means for calculating an existence range of the surface defect or an opening length of the defect based on an output voltage distribution due to the surface defect. Flaw detection equipment.

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